Preparation of urethane and caronate products

ABSTRACT

The present invention provides a process for preparing urethanes and carbonates from an amine or an alcohol, carbon dioxide and a hydrocarbyl halide. The amine or alcohol is reacted with carbon dioxide in a suitable solvent system and in the presence of an amidine or guanidine base, to form the ammonium carbamate or carbonate salt which is then reacted in a polar aprotic solvent with a hydrocarbyl halide. Polymer products can also be prepared utilizing this process or utilizing the resulting urethanes and carbonates under standard polymerization conditions.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of pending application Ser. No.692,857, filed Apr. 29, 1991 now U.S. Pat. No. 5,223,638.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for preparing urethanes andcarbonates and, more particularly, relates to a new and useful processfor preparing urethanes from amines, carbon dioxide and a hydrocarbylhalide and for preparing carbonates from alcohols, carbon dioxide and ahydrocarbyl halide. The present invention also relates to polymersprepared from such urethanes and/or carbonates.

2. Prior Art

Urethanes and carbonates are typically synthesized by the reaction of aprimary amine or an alcohol with phosgene to form an isocyanate orcarbonate salt. Thereafter, the isocyanate or carbonate is reacted withan alcohol to form the corresponding urethane or carbonate. Phosgene isvery toxic and thus requires very careful handling from a product andworker safety standpoint. Isocyanates are sensitizers and are extremelytoxic as well. Preparing urethane and carbonate products without usingphosgene and in an economical manner, and preparing urethane productswithout generating isocyanates would be an achievement of considerablesignificance in the art.

U.S. Pat. No. 4,467,089 discloses the preparation of certain carbamicacid derivatives (carbonates and carbamate esters) by the simultaneousreaction of a secondary amine and a tertiary amine with carbon dioxideto produce corresponding tertiary amine salts of N-substituted carbamicacid. The secondary and tertiary amines are brought together inequimolar proportions in the presence of excess carbon dioxide undermild conditions. The secondary amine reacts with CO₂ in the presence ofthe tertiary amine to form the corresponding disubstituted tertiaryammonium carbamate salt. The salt is described as being useful as heatactivatable delayed action catalysts, especially for use in polyurethaneformulations.

Yoshida et al, Bull. Chem. Soc. Jpn., 62, 1534-38 (1989) disclosespreparation of urethanes from amines, carbon dioxide and alkyl halides.However, under the reaction conditions specified therein, yields ofurethane product are poor as nitrogen derived products are thepredominant product.

In Chemistry Express, Vol. 1, No. 4, pp 224-227 (1986), Kinki ChemicalSociety, Japan, it is disclosed that primary and secondary amines absorbCO₂ to form carbamic acid amine salts and that when an equivalent of1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is added, additional CO₂ isabsorbed to form the DBU-carbamate salt. The DBU-carbamate salt whenreacted in a nonpolar aprotic solvent with an alkylating agent forms acarbamate ester (urethane). Yield and selectivity of the urethaneproduct are highly dependent on the nature of the alkylating agent. Whendibutylamine is reacted with CO₂ in the presence of DBU and theresulting DBU-carbamate salt is reacted with butyl chloride as thealkylating agent, a yield of only 17% is realized. With butyl bromide,the yield is 86%. However, when the reaction with butyl bromide wasrepeated, it was observed that this yield could be achieved only if thereaction was allowed to continue for an extensive period of time, suchas from about 18 to about 30 hours. Thus, this reaction, like thereaction disclosed by Yoshida et al, is not commercially practicable.

It has now been discovered that unexpectedly high yields can be achievedin a commercially practicable period of time, i.e. from one-fourth toone-half of the time set forth above, by conducting the reaction in apolar aprotic solvent and in the presence of a strongly basicnitrogen-containing base selected from amidine- and guanidine-typebases.

SUMMARY OF THE INVENTION

The present invention provides a new and useful process for makingurethanes and carbonates. The present invention also provides a new anduseful process for making polyurethanes and polycarbonates. A preferredembodiment of the present inventive process is a process for makingurethanes and carbonates of the following general formula: ##STR1##wherein R₁ represents alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl,and aralkenyl radicals having from 1 to about 22 carbon atoms, providedthat R₁ is not a tertiary radical of the formula (R)₃ C-- or (R)₂C═C(R)--;

A represents a radical selected from the group consisting of --NR₂ R₃,NHCH(R₃)COOH, and OR₄ wherein R, R₂ and R₃ independently representhydrogen and alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl,alkenaryl and alkaryl radicals having from 1 to about 22 carbon atoms,provided that not more than one of R₂ and R₃ in the formula --NR₂ R₃ ishydrogen; R₄ represents alkyl, alkenyl, cycloalkyl, cycloalkenyl,aralkyl, aralkenyl, alkenaryl, and alkaryl radicals having from 1 toabout 22 carbon atoms;

R₂ and R₃ together with the nitrogen may be bound to form a saturated orunsaturated heterocyclic 5 to 9 membered ring radical, such asmorpholino, pyrrolidino, piperidino, and the like. In addition, one ofR₂ or R₃ can be ##STR2## wherein n represents an integer of from 0 toabout 8; R is as defined above, R₁ is as defined above and R₅ representsalkylene radicals, which may be straight-chain or branched, having from1 to about 22 carbon atoms, i.e., the new and novel urethanes of thisinvention may be diurethanes. Likewise, R₄ can be ##STR3## wherein nrepresents an integer of from 0 to about 8; R₁ and R₂ are as definedabove, and R₅ represents alkylene radicals, which may be straight chainor branched, having from 1 to about 22 carbon atoms, i.e., the new andnovel carbonates may be dicarbonates.

The process for preparing the subject urethanes and carbonates ischaracterized by reacting, in the presence of an amidine- orguanidine-type base, a suitable primary or secondary mono- or polyamine,or a suitable primary, secondary or tertiary mono-alcohol or polyol,with carbon dioxide to form the corresponding carbamate salt orcarbonate salt which is then reacted with a hydrocarbyl halide. In orderto achieve high yields in a reasonable period of time, the reactionbetween the salt and the hydrocarbyl halide is carried out in a polaraprotic solvent. Although the reaction between the amine or alcohol andcarbon dioxide can be conducted in a variety of solvents, it ispreferred to conduct such reaction in the polar aprotic solvent as well,primarily for convenience to avoid isolation of the salt.

The present invention is based on nucleophilic attack on the hydrocarbylhalide by carbamate anions pre-made from CO₂, a primary or secondarymono- or polyamine and a tertiary amine base, or by nucleophilic attackof carbonate anions pre-made from CO₂, a primary, secondary or tertiarymono-alcohol or polyol and a tertiary amine base. Urethane products madein accordance with the present invention are useful in specialtychemical applications, such as, for example, as cross-linking agents.Carbonate products made in accordance with this invention are useful inpreparing polymers which are useful in shatter-resistant optical lenses,face shields and windows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of percent calculated carbamic acid, benzyl ester ofdiethylcarbamic acid produced vs. time for reactions run in acetonitrileand toluene as described in Example 47.

FIG. 2 is a plot of percent calculated carbonic acid, phenyl methylester of butylcarbonic acid produced vs. time for reactions run inacetonitrile and toluene as described in Example 47.

DETAILED DESCRIPTION OF THE INVENTION

The urethanes are prepared in accordance with the present invention bybringing into reactive contact a suitable primary or secondary mono- ordiamine, or a mixture thereof, carbon dioxide and an amidine orguanidine base in a confined zone, such as a reactor, to prepare thecorresponding ammonium carbamate salt. Similarly, the carbonates areprepared in accordance with the present invention by bringing intoreactive contact a suitable primary, secondary or tertiary mono-alcoholor diol, or polyol or a mixture thereof, carbon dioxide and a base in aconfined zone, such as a reactor, to prepare the corresponding carbonatesalt. Preferably the amines or alcohols are in solution and the carbondioxide is bubbled through the solution. The reaction proceeds withoutthe need of elevated pressure or temperatures in a slightly exothermicreaction to give either the ammonium salt of the corresponding carbamateanion or the salt of the corresponding carbonate anion. Use of at leastan essentially stoichiometric amount of the base during the reactionwith carbon dioxide provides the desired urethane and carbonateproducts.

The ammonium salt of the carbamate anion is prepared in solution in thepresence of the amidine-or guanidine-type base. The guanidine as well ascertain amidine salts of the carbamate anions are novel and representanother aspect of the present invention. The use of a base shifts theequilibrium toward the production of the carbamate anions. Where thereaction between the primary or secondary amine is carried out in thepresence of a base, the reaction may be represented by the equation (1).The resulting ammonium carbamate salt solutions are normallyhomogeneous.

    R.sub.2 R.sub.3 NH+Base+CO.sub.2 ⃡R.sub.2 R.sub.3 NCO.sup.-.sub.2 HBase.sup.+                               (1)

Equation (2) shows the results of the addition of the carbamate anion toa hydrocarbyl halide.

    R.sub.2 R.sub.3 NCO.sub.2.sup.-  HBase.sup.+ +R.sub.1 Halide(2)

    R.sub.2 R.sub.3 NCO.sub.2 --R.sub.1 +HBase.sup.+ Halide.sup.-

In order to conduct the reaction with reasonable rates and commerciallypracticable yields, addition of the carbamate anion to the hydrocarbylhalide is performed in a polar aprotic solvent. Normally, the reaction,when conducted in a polar aprotic solvent, proceeds smoothly under mildconditions, e.g. at 25° C. and 110 psi carbon dioxide pressure, to givethe corresponding product in high yields.

Suitable primary or secondary amines used to prepare the carbamateesters in accordance with the present invention include amino acids suchas glycine, aspartic acid and the like, amines represented by thefollowing general formula:

    R.sub.2 R.sub.3 NH,

wherein R₂ and R₃ independently represent hydrogen, provided that nomore than one of R₂ and R₃ is hydrogen, alkyl, alkenyl, cycloalkyl,cycloalkenyl, aryl, aralkyl, aralkenyl, alkenaryl and alkaryl radicalshaving from 1 to about 22 carbon atoms, which radicals can bestraight-chain or branched; and a radical represented by the formula--(--R₅ --)_(n) --NHR wherein R represents radicals as defined above forR₂, R₅ represents alkylene radicals having from about 1 to about 22carbon atoms and n represents an integer of from 0 to about 8. Examplesof R₂ and R₃ include methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, t-butyl, n-pentyl, isopentyl, n-hexyl, n-octyl, phenyl,benzyl, and the like. Specific examples of such suitable amines includeN-ethyl(benzyl)amine, N,N-diallyamine; N,N-diethylamine;N-cyclohexylamine; N,N'-dimethylhexamethylene amine and the like. Inaddition, R₂ and R₃ together with the nitrogen can be bound to form asaturated or unsaturated 5 to 9 membered ring radical. Examples of suchring radicals include morpholino, pyrrolidino, piperidino, and the like.Suitable amines also include polyamines such as, for example,tetraethylene pentamine, diethylene triamine, triethylene tetramine andpentaethylene hexamine and the like, as well as amino acids such asalanine, arginine, asparagine, aspartic acid, cysteine, glutamineglutamic acid, glycine, histidine, isoleucine, leucine, lysine,methionine, phenylalanine, proline, serine, threonine, tryptophan,tyrosine, valine, t-butyl glycine, ornithine, norleucine and the like,including β-amino acids and homo-β-amino acids.

The amine reacts with CO₂ to reversibly form the corresponding ammoniumcarbamate salt. To shift the equilibrium reaction more favorably to theammonium carbamate salt, a strongly basic nitrogen-containing base isadded. Such nitrogen bases include amidines (e.g., DBU,1,8-diazabicyclo[5.4.0]undec-7-ene, etc.) and guanidines (e.g.,cyclohexyltetramethylguanidine, cyclohexyltetraethylguanidine, and thelike).

The salt of the carbonate anion can be prepared in solution in thepresence of a nitrogen-containing base selected from amidines andguanidines. The guanidine as well as certain amidine salts of thecarbonate anions are novel and represent another aspect of the presentinvention. The reaction between the alcohol and carbon dioxide can berepresented by the equation (3). The resulting carbonate salt solutionsare normally homogeneous.

    R.sub.7 R.sub.8 R.sub.9 COH+Base+CO.sub.2 ⃡R.sub.7 R.sub.8 R.sub.9 COCO.sub.2.sup.-  HBase.sup.+                     (3)

Equation (4) shows the results of the addition of the complex ofequation 3 to a hydrocarbyl halide.

    R.sub.7 R.sub.8 R.sub.9 COCO.sub.2.sup.-  HBase.sup.+ +R.sub.4 Halide(4)

    R.sub.7 R.sub.8 R.sub.9 COCO.sub.2 R.sub.4 +HBase.sup.+  Halide.sup.-

Typically, the reaction, when conducted in a polar aprotic solvent,proceeds smoothly under mild conditions, e.g., at 25° C. and 110 psi CO₂pressure, to give the corresponding product in high yield.

Suitable primary, secondary and tertiary alcohols used to prepare thecarbamate esters in accordance with the present invention can berepresented by the following general formula:

    R.sub.7 R.sub.8 R.sub.9 COH

wherein R₇, R₈, and R₉ independently represent hydrogen, and alkyl,alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aralkenyl, alkenaryl andalkaryl radicals having from 1 to about 22 carbon atoms, which radicalscan be straight-chain or branched; a radical represented by the formula--(--R₅ --)_(n) --OH wherein and n are as defined above; or when takentogether along with C form an aromatic ring structure. Examples of R₇,R₈, and R₉ include methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, t-butyl, n-pentyl, isopentyl, n-hexyl, n-octyl, benzyl, andthe like. Specific examples of suitable alcohols include benzyl alcohol,cyclohexanol, ethanol, n-butanol, isopropanol and the like. Suitablealcohols also include diols and polyols such as, for example, ethyleneglycol, sorbitol, pentaerythritol and the like.

An advantage of the present process is that the reaction between theamine or the alcohol and CO₂ proceeds under mild temperature andpressure. Room temperature and a pressure of 110 psi CO₂ are suitableand are preferred. However, if desired, the reaction can be carried outbetween about 25° C. and about 150° C. under a CO₂ pressure in a rangeof from about 2 psi to about 400 psi, such as from about 10 psi to about200 psi. A preferred temperature range is from about 30° C. to about125° C., such as from about 35° C. to about 80° C.

Hydrocarbyl halides suitable for use in the present invention can berepresented by the formula R₁ X wherein R₁ represents alkyl, alkenyl,cycloalkyl, cycloalkenyl, aralkyl and aralkenyl radicals having from 1to about 22 carbon atoms, provided that R₁ is not a tertiary radical ofthe formula (R)₃ C-- or (R)₂ C═C(R)-- and X represents Cl, Br, I and F.Examples of such hydrocarbyl halide include alkyl, cycloalkyl, alkenyl,aralkyl halides. Specific examples of such halides include methylchloride, methyl iodide, ethyl bromide, n-butyl bromide, n-butylchloride, iso-butyl chloride, amyl chloride, n-octyl chloride, benzylbromide, benzyl chloride, (2-naphthyl)methyl chloride,3-chlorocyclohexene, 3-chlorocyclohexane, 2-methyl allyl chloride,4-chloro-2-butene and the like. Hydrocarbyl dihalides and polyhalidesmay also be used. For example, 1,4-dichloro-2-butene,1,4-dichlorobutane, dichloro-p-xylene, and the like, may be utilized.The present invention is also applicable to formation of cycliccarbamates and carbonates wherein a suitable alcohol or amine, asdescribed above, containing a suitable leaving group such as a halide isreacted with CO₂ as set forth herein, in the presence of an amidine orguanidine base.

The reaction between the salt and the hydrocarbyl halide is carried outin a suitable polar aprotic organic solvent. As utilized herein, thephrase "polar aprotic organic solvent" means an aprotic organic solventhaving a dielectric constant of greater than about 10ε as reported inReichardt, C., "Solvents and Solvent Effects in Organic Chemistry," 2nded., VCH Verlagsgesellschaft, Weinheim, (1988), Table A-1, utilizingtoluene (2.38ε) and tetrahydrofuran (7.58ε), both at 20° C., asstandards. Other methods for determining dielectric constants are knownand suitable solvents are those having a dielectric constant greaterthan that of tetrahydrofuran utilizing any of such methods. Examples ofsuitable solvents include acetonitrile, N-methyl pyrrolidone,dimethylformamide, dimethylsulfoxide, and the like, as well as mixturesthereof. Preferred solvents are acetonitrile and DMSO. Although notspecifically required, it is preferred to utilize these same solvents tocarry out the reaction between the amine or alcohol and carbon dioxidein order to avoid the step of isolating the salt. However, this reactioncan also be conducted in other organic solvents which are not polaraprotic solvents, such as, for example, THF, methylene chloride and thelike.

To obtain high selectivity for urethanes over amine products (oxygen vs.nitrogen attack) and high selectivity for carbonates over ethers, theanion is stabilized by the use of an essentially stoichiometric amountof a base. The term base as utilized herein refers to a base utilized inaddition to the reactant amine or alcohol. This is the strongly basicnitrogen-containing base, e.g., a sterically-hindered tertiary aminebase. Addition of the pre-made carbamate, or carbonate, anion undercarbon dioxide pressure to a solution of a hydrocarbyl halide in asuitable polar aprotic solvent gives high yields and selectivities ofurethanes and carbonates and with high rates. The selection of the basein the formation of the carbamate or carbonate is important in order toobtain higher selectivities and thus higher yields. The base preferablyhas one of the general structures shown below. ##STR4## These bases areknown in the art and several are commercially available. Examples ofsuch bases include 1,5-diazabicyclo[4.3.0]non-5-ene (DBN);1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU);7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD); cycohexyltetrabutyl guanidine (CyTBG) and cyclohexyl tetramethyl guanidine(CyTMG). Preferably, the molar ratio of base to the amine or alcoholstarting materials will be within the range of from about 1:1 to about10:1. A preferred molar ratio is in the range of from about 1:1 to about1.5:1. A most preferred molar ratio is 1:1. The rate of reaction betweenthe carbamate or carbonate salts and the hydrocarbyl halide can beincreased by utilizing excess, up to about 2 moles per mole of carbamateor carbonate, hydrocarbyl halide. It is believed that use of such excesshydrocarbyl halide facilitates reaction conditions which arepseudo-first order as opposed to second order. Thus, in order to renderthe present process more commercially practicable, it is preferred touse an excess of such hydrocarbyl halide.

It is contemplated that mixtures of alcohols and mixtures of amines canbe utilized effectively in the process of the present invention.Furthermore, it is contemplated that compounds which include bothalcohol and amine functional groups, e.g., diethanolamine, can beutilized effectively in the process of the present invention. Inaddition, it is contemplated that an alcohol/amine mixture, e.g., amixture of N-benzyl-N-ethyl amine and benzyl alcohol, can be utilizedeffectively in the process of the present invention. It is alsocontemplated that carbon disulfide can be utilized in place of carbondioxide to produce the corresponding dithiocarbamates anddithiocarbonates.

Contemplated equivalents of the general formulas set forth above for thealcohols, amines and hydrocarbyl halides are compounds otherwisecorresponding thereto and having the same general properties wherein oneor more of the various R groups are simple variations of thesubstituents as defined therein, e.g., wherein R is a higher alkyl groupor includes a substituent such as, for example, a halide, aminosubstituents, hydroxy substituents and the like. In addition, where asubstituent is designated as, or can be, a hydrogen, the exact chemicalnature of a substituent which is other than hydrogen at that position isnot critical so long as it does not adversely affect the overallsynthesis procedure. For example, where the above-specified alcohols andamines are mono- and difunctional alcohols and amines, equivalentsthereof which are suitable for use in the present invention includepolyols and polyamines. Where a halide is considered a leaving group,for example, as in the hydrocarbyl halide, other leaving groups such astosyl, mesylate, triflate and the like, which are all well known in theart, are contemplated equivalents.

The chemical reactions described above are generally disclosed in termsof their broadest application to the preparation of the compounds ofthis invention. Occasionally, the reactions may not be applicable asdescribed to each compound included within the disclosed scope. Thecompounds for which this occurs will be readily recognized by thoseskilled in the art. In all such cases, either the reactions can besuccessfully performed by conventional modifications known to thoseskilled in the art, e.g., by appropriate protection of interferinggroups, by changing to alternative conventional reagents, by routinemodification of reaction conditions, and the like, or other reactionsdisclosed herein or otherwise conventional, will be applicable to thepreparation of the corresponding compounds of this invention. In allpreparative methods, all starting materials are known or readilypreparable from known starting materials.

The invention will now be further disclosed in the following illustratedexamples wherein parts and percentages are given on a molar basis unlessotherwise specified.

All amines and alcohols used in the following examples were obtainedeither from Aldrich Chemical Company or Kodak Chemical Company and wereused as received. Anhydrous solvents under nitrogen were purchased fromAldrich Chemical Co. DBN (1,5-diazabicyclo[4.3.0]non-5-ene and DBU(1,8-diazabicyclo[5.4.0]undec-7-ene, were also purchased from AldrichChemical Co.; MTBD (7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene wasobtained from Fluka; CyTMG (cyclohexyl tetramethyl guanidine), as wellas the other cyclohexyl tetraalkyl guanidines were synthesized accordingto the general procedure set forth in Bredereck H.; Bredereck K. ChemBer, 94, (1961) 2278-2295. Thus,N-cyclohexyl-N',N',N",N"-tetrabutylguanidine was synthesized accordingto the following procedure:

In a 3-l, 3-neck flask equipped with a dropping funnel, mechanicalstirrer, and N₂ -bubbler, 1 mole tetrabutylurea was added and dissolvedin 500 mL toluene. One mole POCl₃ was added dropwise over a 30-minuteperiod. The reaction was allowed to stir for 5 h at room temperature and2.2 mole cyclohexylamine was added dropwise over a 30 minute period. Thereaction was allowed to stir at room temperature for 20 h. After thisperiod of time, the reaction was quenched with 500 mL of water. Themixture was allowed to stir vigorously for 15 minutes and then the toptoluene layer was discarded. Excess solid NaOH was added to the bottomlayer until two new layers were formed. The solid was filtered off andthe two layers of the filtrate were separated. The bottom layer wasdiscarded and the process was repeated with the top layer. Again, themixture was filtered and the layers were separated. The bottom layer wasdiscarded and the top layer was dissolved in diethyl ether. The ethersolution was dried over Na₂ CO₃, filtered and concentrated. The base waspurified by distillation.

Gas chromatographic analysis was performed on a Varian Model 3400 gaschromatograph with a model 8000 auto sampler using a 30 meter MegaboreDB-1 (3 μm) J & W Scientific column. Urethane products were purified andwere identified by ¹ H NMR, ¹³ C NMR, mass spectroscopy, IR, andelemental analysis. Nuclear Magnetic Resonance spectra were obtained onVarian VXR-300 or VXR-400 spectrometers. Mass spectra were obtained byFAB or by chemical ionization techniques using isobutane as reagent gas.Infrared spectra were obtained on a Nicolet FTIR. Molecular weightdeterminations of polymers were obtained on GPC Waters System comprisedof a WISP 700 autosampler, 600E system controller, 500Å, 10³ Å, 10⁴ Åand 10⁵ Å gel permeation columns in series, 410 DifferentialRefractometer and a Maxima 820 workstation. Molecular weights are basedon polystyrene standards.

EXAMPLE 1

This example illustrates N-butyl-benzylcarbamate generation utilizing avariety of bases and demonstrates that an amidine- or guanidine-typebase is required. The bases utilized in Rxn #s 4-15 are amidine orguanidine bases whereas those of Rxn #s 1-3 are not. General procedure:A Fischer Porter bottle was charged with 1.46 g (0.02 mol) butyl amine,(0.027 mol) base, 154 mg (0.001 mol) biphenyl as internal G.C. standard,and 20 mL CH₃ CN. The Fischer-Porter bottle was attached to a pressurehead and at room temperature with stirring was added 80 psig carbondioxide. Addition of CO₂ resulted in an exothermic reaction with a risein temperature to ca. 40° C. Into a second Fischer-Porter bottle wasadded 10.12 g (0.08 mol) benzyl chloride in 10 mL CH₃ CN. This mixturewas attached to a pressure head and 80 psig carbon dioxide was addedabove the solution. After 1 h the benzyl chloride solution was added allat once under 80 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 55° C. Aliquots were taken periodicallyand were diluted with diethyl ether, Cl⁻⁺ H Base filtered off, and G.C.yields calculated. The results of this study are given in Table 1.

                  TABLE 1                                                         ______________________________________                                         ##STR5##                                                                                                      % Nitrogen                                                         % Urethane derived                                      Rxn #    Base.sup.1   G.C. Yield Products.sup.2                               ______________________________________                                        1        Proton Sponge                                                                               0         63                                           2        BuNH.sub.2    2         77                                           3        PMP           7         92.5                                         4        n-BuTEG      45         24                                           5        t-BuDEF      48         34                                           6        TEG          50         17                                           7        TMG          62         22                                           8        DBU          69         18                                           9        MTDB         86         14                                           10       t-BuDMA      87         18                                           11       CyTEG        92         14                                           12       t-BuTEG      92         13                                           13       CyTMG        94         9                                            14       CyTBG        97         6                                            ______________________________________                                         All reactions run at 55° C. under 80 psig carbon dioxide pressure      and run to completion based on butyl amine.                                   G.C. yields determined using biphenyl as internal standard.                   .sup.1 Proton Sponge = N,N,N',N'-tetramethyl1,8-naphthalenediamine.           PMP = 1,2,2,6,6pentamethylpiperadine.                                         N-BuTEG  Nbutyl-N',N',N",N"-tetraethylguanidine.                              t-BuDEF = Nt-butyl-N',N'-diethylformamidine.                                  TEG = N,N,N',N'-tetraethylguanidine.                                          TMG  N,N,N',N'-tetramethylguanidine.                                          DBU  1,8diazabicyclo[5.4.0]undec 7ene.                                        MTDB = 7methyl-1,5,7-triazabicyclo[4.4.0]dec 5ene.                            t-BuDMA = Nt-butyl-N',N'-dimethylacetamidine.                                 CyTEG = Ncyclohexyl-N',N',N",N"-tetraethylguanidine.                          t-BuTEG = Nt-butyl-N',N',N",N"-tetraethylguanidine.                           CyTMG = Ncyclohexyl-N',N',N",N"-tetramethylguanidine.                         CyTEG = Ncyclohexyl-N',N',N",N"-tetraethylguanidine.                          CyTBG = Ncyclohexyl-N',N',N",N"-tetrabutylguanidine.                          .sup.3 Nitrogen derived products include, Nbutyl-N-benzylamine,               Nbutyl-N,N-dibenzyl amine and Nbutyl-N-benzyl benzylcarbamate (secondary      product derived from the Nbutyl-N-benzyl amine generated). A small amount     of dibenzylcarbonate resulting from trace amounts of water in reagents wa     also detected by G.C.                                                    

EXAMPLE 2

This example illustrates N-butyl-benzylcarbamate generation utilizing avariety of polar aprotic solvents. General procedure: A Fischer Porterbottle was charged with 1.46 g (0.02 mol) butyl amine, (0.027 mol) base(either 1,8-diazabicyclo[5.4.0]undec-7-ene orN-cyclohexyl-N',N',N",N"-tetramethylguanidine), 154 mg (0.001 mol)biphenyl as internal G.C. standard, and 20 mL solvent. TheFischer-Porter bottle was attached to a pressure head and at roomtemperature with stirring was added 80 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a second Fischer-Porter bottle was added 10.12 g (0.08 mol)benzyl chloride in 10 mL solvent. This mixture was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the benzyl chloride solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in thefirst Fischer-Porter bottle. After addition the reaction mixture waswarmed to 55° C. Aliquots were taken periodically and were diluted withdiethyl ether, Cl⁻⁺ H Base filtered off, and G.C. yields calculated. Theresults of this study are given in Table 2.

                  TABLE 2                                                         ______________________________________                                         ##STR6##                                                                                                         % Nitrogen                                                          % Urethane                                                                              derived                                   Rxn #  Base.sup.1                                                                              Solvent.sup.2                                                                          G.C. Yield                                                                              Products.sup.3                            ______________________________________                                        1      DBU       N-MF     35        46                                        2      DBU       DMF      57         8                                        3      DBU       N-MP     59        18                                        4      DBU       CH.sub.3 CN                                                                            69        19                                        5      DBU       Sulfolane                                                                              69        28                                        6      CyTMG     Toluene  84         9                                        7      CyTMG     N-MP     59         9                                        8      CyTMG     CH.sub.3 CN                                                                            94         9                                        9      CyTMG     TMU      70        15                                        10     CyTMG     Sulfolane                                                                              89        11                                        ______________________________________                                         All reactions run at 55° C. under 80 psig carbon dioxide pressure      and run to completion based on butyl amine.                                   G.C. yields determined using biphenyl as internal standard.                   .sup.1 DBU = 1,8diazabicyclo[5.4.0]undec 7ene.                                CyTMG = Ncyclohexyl-N',N',N",N"-tetramethylguanidine.                         .sup.2 N-MF = Nmethylformamide.                                               DMF = N,Ndimethylformamide.                                                   N-MP = 1methyl-2-pyrrolidinone.                                               TMU = tetramethylurea.                                                        .sup.3 Nitrogen derived products include, Nbutyl-N-benzyl amine,              NbutylN,N-dibenzyl amine and Nbutyl-N-benzyl benzylcarbamate (secondary       product derived from the Nbutyl-N-benzyl amine generated). A small amount     of dibenzyl carbonate resulting from trace amounts of water in reagents       was also detected by G.C.                                                

The following examples namely Examples 3-5illustrate a variety ofurethanes prepared according to the teachings of the present invention.For comparison purposes a summary of these examples is set forth inTable 3.

EXAMPLE 3

N,N-dibutyl benzylcarbamate (1)

A Fischer-Porter bottle was charged with 2.58 g (0.02 mol) dibutylamine, 3.94 g (0.02 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine,154 mg (0.001 mol ) biphenyl as internal G.C. standard, and 20 mL CH₃CN. The Fischer-Porter bottle was attached to a pressure head and atroom temperature with stirring was added 80 psig carbon dioxide.Addition of CO₂ resulted in an exothermic reaction with a rise intemperature to ca. 40° C. Into a second Fischer-Porter bottle was added10.12 g (0.08 mol) benzyl chloride in 10 mL CH₃ CN. This mixture wasattached to a pressure head and 80 psig carbon dioxide was added abovethe solution. After 1 h the benzyl chloride solution was added all atonce under 80 psig CO.sub. 2 to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 40° C. for 3 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. An aliquot was taken, diluted with diethyl ether,Cl⁻⁺ HCyTMG precipitated from solution and was filtered off, and by G.C.analysis a 95% yield of urethane was calculated. The crude material waspoured into 100 mL ethyl acetate and extracted with 2×100 mL 0.5 M aq.HCl followed by 100 mL brine. The organic layer was dried over Na₂ CO₃filtered and concentrated leaving a light yellow oil. This oil waschromatographed on silica gel using first 100% hexane (to remove excessbenzyl chloride and internal G.C. standard) and then with 100% CH₂ Cl₂.The O-benzyl carbamate product, 1, was isolated as a clear oil (3.38 g,64%). Oil ¹ H NMR (CDCl₃) δ7.39-7.30 (overlapping m, 5H), 5.17 (s, 2H),3.27 (br, 4H), 1.55 (br, 4H), 1.33 (br m, 4H), 0.94 (br, 6H). ¹³ C{¹ H}NMR (CDCl₃) δ156.7, 137.7, 128.9, 128.3, 128.2, 67.2, (47.8, 47.2),(31.4, 30.8), 20.5, 14.4. IR (film) 1703; MS (FAB) m/z=264 (MH⁺). Anal.Calcd.: C, 72.97; H, 9.57; N, 5.32. Found: C, 73.22; H, 9.35; N, 5.45.

EXAMPLE 4

N,N-diethyl benzylcarbamate (2)

Procedures as described in synthesis of 1. A G.C. yield of 95% wascalculated and a 47% isolated yield of N,N-diethyl benzylcarbamate, 2resulted. Oil. ¹ H NMR (CDCl₃) δ7.35-7.25 (overlapping m, 5.12 (s, 2H),3.29 (br q, J=6.4 Hz, 4H), 1.15 (t, J=6.9 Hz, 6H). ¹³ C {¹ H} NMR(CDCl₃) δ8 155.7, 137.1, 128.4, 127.7, 127.6, 66.7, 41.6 (br), 13.8(br). IR (film) 1700; MS (EI) m/z=207 (M⁺) .

EXAMPLE 5

N-butyl benzyl carbamate (3)

A Fischer Porter bottle was charged with 1.46 g (0.02 mol) butyl amine,5.32 g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine, 154 mg(0.001 mol) biphenyl as internal G.C. standard, and 20 mL CH₃ CN. TheFischer-Porter bottle was attached to a pressure head and at roomtemperature with stirring was added 80 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a second Fischer-Porter bottle was added 10.12 g (0.08 mol)benzyl chloride in 10 mL CH₃ CN. This mixture was attached to a pressurehead and 80 psig carbon dioxide was added above the solution. After 1 hthe benzyl chloride solution was added all at once under 80 psig CO₂ tothe pre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the reaction mixture was warmed to55° C. for 18 h. After this time the reaction mixture was allowed tocool to room temperature and then the pressure was released. An aliquotwas taken, diluted with diethyl ether, Cl⁻⁺ HCyTMG precipitated fromsolution and was filtered off, and by G.C. analysis a 95% yield ofurethane was calculated. The crude material was poured into 100 mL ethylacetate and extracted with 2×100 mL 0.5M HCl followed by 100 mL brine.The organic layer was dried over Na₂ CO₃ filtered and concentratedleaving a light yellow oil. This oil was chromatographed on silica gelusing first 100% hexane (to remove excess benzyl chloride and internalG.C. standard) and then with 100% CH₂ Cl₂. The O-benzyl carbamateproduct, 3, was isolated as a clear oil (2.64 g, 64%) . Oil. ¹ H NMR(CDCl₃) δ7.40-7.34 (overlapping m, 5H), 5.14 (s, 2H), 4.9 (br s, N--H),3.21 (br q, J=5.1 Hz, 2H), 1.51 (m, 2H), 1.38 (m, 2H), 0.96 (t, J=7.2Hz, 3H). ¹³ C {¹ H} NMR (CDCl₃) δ156.4, 136.6, 128.4, 128.2, 127.9,66.4, 40.7, 31.9, 19.7, 13.6. IR (film) 3337, 1701; MS m/z=(MH⁺).

EXAMPLE 6

N-sec-butyl benzyl carbamate (4)

Procedures are described in synthesis of 3. A G.C. yield of 89% wascalculated and a 44% isolated yield of N-s-butyl benzylcarbamate, 4resulted. m.p. 49°-50.5 ° C. ¹ H NMR (CDCl₃) δ7.41-7.30 (overlapping m,5H), 5.14 (s, 2H), 4.6 (br s, N--H), 3.69 (m, 1H), 1.50 (quintet, J=7Hz, 2H), 1.17 (d, J=6.6 Hz, 3H), 0.95 (t, J=7.4 Hz, 3H). ¹³ C {¹ H} NMR(CDCl₃) δ155.8, 136.7, 128.4, 128.2, 127.9, 66.4, 48.4, 29.8, 20.7,10.2. IR (CDCl₃) 3441, 1713; MS (EI) m/z=207 (M⁺). Anal. Calcd.: C,69.54; H, 8.27; N, 6.76. Found: C, 69.71; H, 8.49; N, 6.87.

EXAMPLE 7

N-tert-butyl benzyl carbamate (5)

Procedures as described in synthesis of 3. A G.C. yield of 90% wascalculated and a 41% isolated yield of N-t-butyl benzylcarbamate, 5resulted. Oil. ¹ H NMR (CDCl ₃) δ7.38-7.32 (overlapping m, 5H), 5.09 (s,2H), 4.9 (br, N--H), 1.36 (s, 9H). ¹³ C {¹ H} NMR (CDCl₃) δ155.3, 137.4,129.0, 128.6, 128.5, 66.5, 50.8, 29.5. IR (film) 3346, 1711 (literature1710); MS (EI) m/z=207 (M⁺). Anal. Calcd.: C, 69.54; H, 8.27; N, 6.76.Found: C, 69.53; H, 8.14; N, 6.97.

EXAMPLE 8

N-octyl benzylcarbamate (6)

Procedures as described in synthesis of 3. A G.C. yield of 99.5% wascalculated and a 53% isolated yield of N-octyl benzylcarbamate, 6resulted after crystallization from hexane. m.p. 32°-33° C. ^(l) H NMR(CDCl₃) δ7.41-7.29 (overlapping m, 5H), 5.08 (s, 2H), 4.77 (s, N--H),3.17 (q, J=6.7 Hz, 2H), 1.48 (m, 2H), 1.26 (overlapping m, 10H), 0.87(t, J=6.7 Hz, 3H). ¹³ C {¹ H} NMR (CDCl₃) δ156.4, 136.7, 128.5, 128.1,128.0, 66.6, 41.1, 31.8, 30.0, 29.3, 29.2, 26.7, 22.6, 14.0. IR (CDCl₃)3451, 1713; MS m/z=(MH⁺). Anal. Calcd.: C, 72.97; H, 9.57; N, 5.32.Found: C, 72.86; H, 9.51; N, 5.63.

EXAMPLE 9

N-cyclohexy benzylcarbamate (7)

Procedures as described in synthesis of 3. A G.C. yield of 97% wascalculated and a 50% isolated yield of N-cyclohexyl benzylcarbamate, 7resulted after crystallization from hot hexane. m.p. 93°-94.5° C.(literature, m.p. 93°-94° C.). ¹ H NMR (CDCl₃) δ7.40-7.30 (overlappingm, 5H), 5.13 (s, 2H), 4.7 (br, N--H), 3.54 (m, 1H), 1.99-1.1(cyclohexyl, 10H). ¹³ C {¹ H} NMR (CDCl₃) δ155.5, 136.7, 128.5, 128.1,128.0, 66.4, 49.9, 33.4, 25.5, 24.7. IR (CHCl₃) 3441, 1711; MS (EI)m/z=233 (M⁺). Anal. Calcd.: C, 72.07; H, 8.21; N, 6.00. Found: C, 72.45;H, 8.36; N, 5.98.

EXAMPLE 10

N-cyclohexanemethyl benzylcarbamate (8)

Procedures as described in synthesis of 3. A G.C. yield of 105% wascalculated and a 76% isolated yield of N-cyclohexanemethylbenzylcarbamate, 8 resulted after crystallization from hot hexane. m.p.58.5°-61°C. ¹ H NMR (CDCl₃) δ7.4-7.3 (overlapping m, 5H), 5.13 (s, 2H),4.90 (br, N--H), 3.07 (t, J=6.5 Hz, 2H), 1.8-0.9 (overlapping m, 11H).¹³ C {^(l) H} NMR (CDCl₃) δ157.1, 137.3, 129.0, 128.6, 128.5, 67.1,47.9, 38.8, 31.2, 26.9, 26.3. IR (CHCl₃) 3455, 1713; MS m/z=248 (MH⁺).Anal. Calcd.: C, 72.84; H, 8.56; N, 5.66. Found: C, 72.84; H, 8.54; N,5.63.

EXAMPLE 11

N-cyclohexanemethyl benzylcarbamate (9)

Procedures as described synthesis of 3. A G.C. yield of 90% wascalculated and a 64% isolated yield of N-phenyl benzylcarbamate, 9resulted after crystallization from ether/hexane. m.p. 79°-80.5° C. ¹ HNMR (CDCl₃) δ7.47-7.33 (overlapping m, 8H), 7.12 (t, J=7.3 Hz, 2H), 6.81(br, N--H), 5.25 (s, 2H). ¹³ C {¹ H} NMR (CDCl₃) δ153.9, 138.3, 136.6,129.6, 129.2, 128.9, 124.1, 119.3, 67.6. IR (CHCl₃) 3435, 1734; MS (EI)m/z=227 (M⁺). Anal. Calcd.: C, 73.99; H, 5.77; N, 6.16. Found: C, 73.84;H, 5.80; N, 6.22.

EXAMPLE 12 Tris-benzyl carbamate of N'N',N"-bis(ethylene diamine) (10)

A Fischer Porter bottle was charged with 1.03 g (0.01 mol) bis-ethylenetri-amine, 7.39 g (0.0375 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine, and 20 mL CH₃ CN. TheFischer-Porter bottle was attached to a pressure head and at roomtemperature with stirring was added 80 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a second Fischer-Porter bottle was added 11.48 g (0.09 mol)benzyl chloride in 10 mL CH₃ CN. This mixture was attached to a pressurehead and 80 psig carbon dioxide was added above the solution. After 1 hthe benzyl chloride solution was added all at once under 80 psig CO₂ tothe pre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the reaction mixture was warmed to55° C. for 18 h. After this time the reaction mixture was allowed tocool to room temperature and then the pressure was released. The crudematerial was poured into 100 mL ethyl acetate and extracted with 2×100mL 0.5M aq. HCl followed by 100 mL brine. The organic layer was driedover MgSO₄, filtered and concentrated. The residue was dissolved inhexane and upon cooling a solid precipitated. After recrystallizationfrom ethyl acetate/hexane an isolated yield of 53% (2.7 g) of thetricarbamate 10 resulted. m.p. 67°-68° C. ¹ H NMR (CDCl₃) 7.4-7.3(overlapping m, 15H), 5.5 (br, N--H, 1H), 5.1 (br, N--H, 1H), 5.1 (s,6H), 3.5-3.3 (overlapping br m, 8H). ¹³ C{¹ H} NMR (CDCl₃) 157.4, 157.3(br), 137.1 (br), 136.8, 129.1, 129.0, 128.7, 128.6, 128.5, 68.1, 67.2,48.3 (br), 40.5 (br). IR (CHCl₃) 3451, 1711; MS (thermal spray) m/z=506(MH⁺). Anal. Calcd.: C, 66.52; H, 6.18; N, 8.31. Found: C, 66.60; H,6.35;, N, 8.30.

EXAMPLE 13

4,4'-methylene-bis(cyclohexyl)-bis-(benzylcarbamate) (11)

A Fischer Porter bottle was charged with 2.1 g (0.01 mol)4,4'-methylenebis(cyclohexylamine), 4.14 g (0.021 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine, and 20 mL1-methyl-2-pyrrolidinone (N-MP). The Fischer-Porter bottle was attachedto a pressure head and at room temperature with stirring was added 80psig carbon dioxide. Addition of CO₂ resulted in an exothermic reactionwith a rise in temperature to ca. 40° C. Into a second Fischer-Porterbottle was added 5.06 g (0.04 mol) benzyl chloride in 10 mL N-MP. Thismixture was attached to a pressure head and 80 psig carbon dioxide wasadded above the solution. After 1 h the benzyl chloride solution wasadded all at once under 80 psig CO₂ to the pre-formed carbamate anionsolution generated in the first Fischer-Porter bottle. After additionthe reaction mixture was warmed to 55° C. for 16 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 200 mL H₂ Oand a white precipitate formed. This white material was collected byfiltration and was washed with water followed by air drying at roomtemperature overnight giving 3.63 g (78%) of the dicarbamate 11. IR(CHCl₃) 3441, 1713. Anal. Calcd.: C, 72.77; H, 8.0; N, 5.85. Found: C,72.79; H, 8.16; N, 5.94.

EXAMPLE 14

TAN-tribenzylcarbamate (12)

A 160 cc stainless steel Parr autoclave was charged with 5.19 g (0.03mol) 4-aminomethyl-1,8-octanediamine (TAN), 17.9 g (0.096 molN-cyclohexyl-N',N',N",N"-tetramethylguanidine, and 30 mL1-methyl-2-pyrrolidinone (N-MP). The autoclave was attached to apressure head and at room temperature with stirring was added 160 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction witha rise in temperature to ca. 40° C. Into a Fischer-Porter bottle wasadded 22.8 g (0.18 mol) benzyl chloride. This was attached to a pressurehead and 80 psig carbon dioxide was added above the solution. After 1 hthe benzyl chloride solution was added all at once under 80 psig CO₂ tothe pre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the pressure was raised again to160 psig with carbon dioxide and the reaction mixture was warmed to 55°C. for 18 h. After this time the reaction mixture was allowed to cool toroom temperature and then the pressure was released. The crude materialwas poured into 100 mL ethyl acetate and extracted with 2×100 mL 0.5Maq. HCl followed by 100 mL brine. The organic layer was dried over Na₂CO₃, filtered and concentrated. After crystallization from ethylacetate/hexane an isolated yield of 58% (9.01 g) of the tricarbamate 12resulted. m.p. 78°-80° C. ¹ H NMR (CDCl₃) δ7.4-7.34 (m, 5H), 5.1 (s,6H), 5.1-5.0 (br, N--H, 3H), 3.2-3.05 (m, 6H), 1.6-1.2 (overlapping m,11H) . ¹³ C{¹ H} NMR (CDCl₃) δ157.4, 157.1, 137.2, 129.0, 1286, 67.2,67.1, 44.0, 41.6, 38.6, 31.4, 30.7, 28.9, 27.3, 23.9. IR (CHCl₃) 3453,1713. Anal. Calcd.: C, 68.85; H, 7.18; N, 7.30. Found: C, 69.39; H,7.32; N, 7.32.

EXAMPLE 15

Hexmethylene-1,6-bis(benzylcarbamate) (13)

A 160 cc stainless steel Parr autoclave was charged with 4.64 g (0.04mol) 1,6-diaminohexane, 16.75 g (0.085 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine, and 30 mL1-methyl-2-pyrrolidinone (N-MP). The autoclave was attached to apressure head and at room temperature with stirring was added 160 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction witha rise in temperature to ca. 40°C. Into a Fischer-Porter bottle wasadded 20 g (0.158 mol) benzyl chloride. This was attached to a pressurehead and 80 psig carbon dioxide was added above the solution. After 1 hthe benzyl chloride solution was added all at once under 80 psig CO₂ tothe pre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the pressure was raised again to160 psig with carbon dioxide and the reaction mixture was warmed to 55°C. for 18 h. After this time the reaction mixture was allowed to cool toroom temperature and then the pressure was released. The crude materialwas poured into 200 mL H₂ O and a white precipitate formed. This whitematerial was collected by filtration and was washed with water followedby air drying at room temperature overnight giving 9.75 g (63.5%) of thedicarbamate 13. m.p. 130°-132° C. ¹ H NMR (CDCl₃) δ7.4-7.3 (overlappingm, 10H), 5.13 (s, 4H), 4.85 (br, N--H, 2H), 3.21 (q, J=6.3 Hz, 4H), 1.52(br m, 4H), 1.36 (br, 4H). ¹³ C{¹ H} NMR (CDCl₃) δ157.0, 137.2, 129.0,128.6 (overlapping), 67.1, 41.4, 30.4, 26.7. IR (CHCl₃) 3453, 1713; MS(FAB) m/z=385 (MH⁺). Anal. Calcd.: C, 68.73; H, 7.34; N, 7.29. Found: C,68.70; H, 7.40; N, 7.19.

                                      TABLE 3                                     __________________________________________________________________________     ##STR7##                                                                                               % Urethane                                                                    G.C. Yield                                                                            Isolated                                                                           % Amine.sup.1                          Example #                                                                           RR'NH     Temp °C.                                                                    Solvent                                                                            (Compound #)                                                                          Yield                                                                              G.C. Yield                             __________________________________________________________________________    3     Bu.sub.2 NH                                                                             40   CH.sub.3 CN                                                                        95(1)   64   <1                                     4     Et.sub.2 NH                                                                             40   CH.sub.3 CN                                                                        95(2)   47   <1                                     5     BuNH.sub.2                                                                              55   CH.sub.3 CN                                                                        95(3)   64    9                                     6     s-BuNH.sub.2                                                                            55   CH.sub.3 CN                                                                        89(4)   44   <1                                     7     t-BuNH.sub.2                                                                            55   CH.sub.3 CN                                                                        90(5)   41   <1                                     8     c-C.sub.8 H.sub.17 NH.sub.2                                                             55   CH.sub.3 CN                                                                        99.5(6) 53   <1                                     9     CyNH.sub.2                                                                              55   CH.sub.2 CN                                                                        97(7)   50   <1                                     10    CyCH.sub.2 NH.sub.2                                                                     55   CH.sub.3 CN                                                                        105(8)  76   <1                                     11    PhNH.sub.2                                                                              55   CH.sub.3 CN                                                                        90(9)   64   <1                                     12    (NH.sub.2 CH.sub.2 CH.sub.2).sub.2 NH                                                   55   CH.sub.3 CN                                                                         --(10) 50   --                                     13    1,4-(NH.sub.2 Cy).sub.2 CH.sub.2                                                        55   NMP.sup.3                                                                           --(11) 78   --                                     14    Triaminononane.sup.2                                                                    55   NMP.sup.3                                                                           --(12) 58   --                                     15    H.sub.2 N(CH.sub.2).sub.6 NH.sub.2                                                      55   NMP.sup.3                                                                           --(13) 63.5 --                                     __________________________________________________________________________     All reactions were run under 80 psig carbon dioxide pressure and run to       completion, limiting reagent is the amine. An excess of benzyl chloride a     used in all reactions and G.C. yields are based on biphenyl internal          standard.                                                                     .sup.1 % Amine indicated by G.C. is the approximate amount of products        derived from nitrogen attack on benzyl chloride.                              .sup.2 Triaminononane = 4aminomethyl-1,8-octanediamine.                       .sup.3 NMP = 1methyl-2-pyrrolidinone.                                    

EXAMPLE 16

Cbz-dibenzylasparate (14)

A Fischer Porter bottle was charged with 2.66 g (0.02 mol) L-asparticacid, 12.77 g (0.084 mol) 1,8-diazabicyclo[5.4.0]undec-7-ene and 25 mLCH₃ CN. The Fischer-Porter bottle was attached to a pressure head and atroom temperature with stirring was added 80 psig carbon dioxide.Addition of CO₂ resulted in an exothermic reaction with a rise intemperature to ca. 40° C. Into a second Fischer-Porter bottle was added15 g (0.12 mol) benzyl chloride in 10 mL CH₃ CN. This mixture wasattached to a pressure head and 80 psig carbon dioxide was added abovethe solution. After 1 h the benzyl chloride solution was added all atonce under 80 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 55° C. for 3 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 100 mL diethylether and extracted with 2×100 mL 0.5M aq. HCl followed by 100 mL brine.The organic layer was dried over MgSO₄, filtered and concentrated. Theexcess benzyl chloride was removed by adding hexane to the crude residueleaving a light yellow oil. Crystallization form diethyl ether/hexanegave 5.34 g (60%) of Cbz-dibenzyl aspartate 14. Product identified byNMR spectroscopy and was identical to authentic material. [α]_(D) ²³=-1.8 (authentic material=-1.9).

EXAMPLE 17

1,6Hexamethylene-bis-(p-vinylbenzylcarbamate) (15)

A Fischer Porter bottle was charged with 4 g (0.035 mol)1,6-diaminohexane, 14 g (0.092 mol) 1,8-diazabicyclo[5.4.0]undec-7-eneand 30 mL CH₃ CN. The Fischer-Porter bottle was attached to a pressurehead and at room temperature with stirring was added 80 psig carbondioxide. Addition of CO₂ resulted in an exothermic reaction with a risein temperature to ca. 40° C. Into a second Fischer-Porter bottle wasadded 20 g (0.13 mol) p-vinylbenzyl chloride. This was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the benzyl chloride solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in thefirst Fischer-Porter bottle. After addition the reaction mixture waswarmed to 55° C. for 4 h. After this time the reaction mixture wasallowed to cool to room temperature and then the pressure was released.The crude material was poured into 200 mL 0.5M aq. HCl giving a whitesolid. This solid was collected by filtration and was washed with waterfollowed by air drying at room temperature giving 6.8 g (45%) of thedicarbamate 15. m.p. (decomposition >153° C.). ¹ H NMR (CDCl₃) δ7.43 (d,J=8.3 Hz, 4H), 7.34 (d, J=8.1 Hz, 4H), 6.74 (dd, J=17.7, 10.8 Hz, 2H),5.78 (dd, J=17.6, 0.9 Hz, 2H), 5.29 (dd, J=10.8, 0.9 Hz, 2H), 5.11 (s,4H), 4.8 (br, N--H, 2H), 3.20 (br, 4H), 1.50 (br, 4H), 1.35 (br, 2H). ¹³C{1H} NMR (CDCl₃) δ156.9, 138.0, 136.9, 136.7, 128.9, 126.9, 114.7,66.9, 41.4, 30.4, 26.7. IR (CHCl₃) 3452, 1709. Anal. Calcd.: C, 71.53;H, 7.39; N, 6.42. Found: C, 71.72; H, 7.45; N, 6.48.

EXAMPLE 18

αα'-Bis-(N,N-diethyl)-p-xylylcarbamate (16)

A Fischer Porter bottle was charged with 1.46 g (0.02 mol) diethylamine, 3.43 g (0.022 mol) 1,8-diazabicyclo[5.4.0]undec-7-ene and 20 mLN,N-dimethylformamide. The Fischer-Porter bottle was attached to apressure head and at room temperature with stirring was added 80 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction witha rise in temperature to ca. 40° C. Into a second Fischer-Porter bottlewas added 0.88 g (0.005 mol) α,α'-dichloro-p-xylene in 15 ml DMF. Thiswas attached to a pressure head and 80 psig carbon dioxide was addedabove the solution. After 1 h the di-chloride solution was added all atonce under 80 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 40° C. for 21 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 100 mL diethylether and was then extracted with 2×100 mL 0.5M aq. HCl and 100 mLbrine. The ethereal layer was dried over Na₂ CO₃, filtered andconcentrated. The residue was chromatographed on silica gel using 25%ethyl acetate/hexane giving 0.96 g (66%) of the dicarbamate 16. m.p.61°-63 C. ¹ H NMR (CDCl₃) δ7.36 (s, 4H), 5.14 (s, 4H), 3.31 (q, J=6.9Hz, 8H), 1.14 (t, J=7.2 Hz, 12 H). ¹³ {¹ H} NMR (CDCl₃) δ156.3, 137.3,128.3, 66.9, 42 (br), 14.5 (br). IR (CHCl₃) 1692; MS (thermal spray)m/z=337 (MH⁺). Anal. Calcd.; C, 64.26; H, 8.39; N, 8.33. Found: C,64.73; H, 8.60; N, 8.36.

The following Examples 19-30 illustrate the present process utilizingvarious amines, polar aprotic solvents, hydrocarbyl halides and reactiontemperatures. A summary of these examples is set forth in Table 4.

EXAMPLE 19

N,N-dibutyl butylcarbamate (17)

Fischer-Porter bottle was charged with 2.58 g (0.02 mol) N,N-dibutylamine, 5.32 g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine,154 mg biphenyl as internal G.C. standard and 20 mL CH₃ CN. TheFischer-Porter bottle was attached to a pressure head and at roomtemperature with stirring was added 80 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40°C. Into a second Fischer-Porter bottle was added 7.4 g (0.08 mol)butyl chloride in 10 mL CH₃ CN. This was attached to a pressure head and80 psig carbon dioxide was added above the solution. After 1 h thebenzyl chloride solution was added all at once under 80 psig CO₂ to thepre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the reaction mixture was warmed to70° C. for 17.5 h. After this time the reaction mixture was allowed tocool to room temperature and then the pressure was released. An aliquotwas taken, diluted with ether, solid Cl⁻⁺ HCyTMG filtered off andanalyzed by G.C. (93.5% yield calculated). Oil. ¹ H NMR (CDCl₃) δ4.08(t, J=6.6 Hz, 2H), 3.21 (br, 4H), 1.65-1.3 (overlapping m, 12H), 0.95(t, J=7.3 Hz, 3H), 0.94 (t, J=7.3 Hz, 6H). ¹³ C {¹ H} NMR (CDCl₃)δ157.1, 65.3, 47.4 (br), 31.7, 31.2 (br), 20.5, 19.7, 14.4, 14.2. IR(film) 1703; MS m/z=230 (MH⁺) . Anal. Calcd.: C, 68.08; H, 11.87; N,6.11. Found: C, 68.32; H, 10.92; N, 6.06.

EXAMPLE 20

N,N-diethyl butylcarbamate (18)

A 160 cc stainless steel Parr autoclave was charged with 2.19 g (0.03mol) diethyl amine, 8.46 g (0.043 mol)N-cyclohexy-N',N',N",N"-tetramethylguanidine, 310 mg (0.002 mol)biphenyl as internal G.C. standard, and 25 mL CH₃ CN. The autoclave wasattached to a pressure head and at room temperature with stirring wasadded 160 psig carbon dioxide. Addition of CO₂ resulted in an exothermicreaction with a rise in temperature to ca. 40° C. Into a Fischer-Porterbottle was added 8.325 g (0.09 mol) butyl chloride in 10 mL CH₃ CN. Thismixture was attached to a pressure head and 80 psig carbon dioxide wasadded above the solution. After 1 h the butyl chloride solution wasadded all at once under 80 psig CO₂ to the pre-formed carbamate anionsolution generated in the autoclave. After addition the pressure wasraised to 160 psig with carbon dioxide and the reaction mixture waswarmed to 70 ° C. for 1.5 h. After this time the reaction mixture wasallowed to cool to room temperature and then the pressure was released.An aliquot was taken, diluted with diethyl ether, Cl⁻⁺ HCyTMGprecipitated from solution and was filtered off, and by G.C. analysis a97% yield of urethane was calculated. The crude material was poured into100 mL ethyl acetate and extracted with 2×100 mL 0.5M aq. HCl followedby 100 mL brine. The organic layer was dried over Na₂ CO₃, filtered andconcentrated leaving a light yellow residue. This was distilled andN,N-diethyl butylcarbamate was collected at 70°-71° C. (ca. 3 torr),3.16 g (61%). Oil. ¹ H NMR (CDCl₃) δ8 4.06 (t, J=6.5 Hz, 2H), 3.26 (q,J=7.1 Hz, 4H), 1.61 (m, 2H), 1.37 (m, 2H), 1.10 (t, J=7.2 Hz, 6H), 0.93(t, J=7.3 Hz, 3H) . ¹³ C {¹ H} NMR (CDCl.sub. 3) δ156.6, 65.3, 41.9,31.7, 19.7, 14.2. IR (film) 1700; MS (thermal spray) m/z=174 (MH⁺).Anal. Calcd.: C, 62.39; H, 11.05; N, 8.08. Found: C, 61.84; H, 10.61; N,7.97.

EXAMPLE 21

N-butyl butylcarbamate (19)

Procedures as described in synthesis of 18, using18-diazabicyclo[5.4.0]undec-7-ene in place of CyTMG. A G.C. yield of 82%was calculated and a 71% isolated yield of N-butyl butylcarbamateresulted after chromatography on silica gel. Oil. ¹ H NMR (CDCl₂) δ4.75(br, N--H), 4.05 (t, J=6.7 Hz, 2H), 3.15 (t, J=6.9 Hz, 2H), 1.61-1.32(overlapping m, 8H) 0.92 (t, J=7.31 Hz, 3H), 0.91 (t, J=7.2 Hz, 3H). ¹³C {H} NMR (CDCl₃) δ157.4, 65.1, 41.3, 32.6, 31.6, 20.4, 19.6, 14.2(overlapping). IR (film) 3337, 1700; MS (thermal spray) m/z=174 (MH⁺).

EXAMPLE 22

N-phenyl butylcarbamate (20)

Procedures as described in synthesis of 18, using1,8-diazabicyclo[5.4.0]undec-7-ene in place of CyTMG. A G.C. yield of67% was calculated and a 58% isolated yield of N-phenyl butylcarbamateresulted after chromatography on silica gel. m.p. 63.5°-65° C. ¹ H NMR(CDCl₃) δ7.44 (d, J=8 Hz, 2H), 7.34 (t, J=8 HZ, 2H), 7.09 (t, J=7.3 Hz,1H), 6.83 (br, N--H), 4.22 (t, J=6.7 Hz, 2H), 1.70 (m, 2H), 1.45 (m,2H), 1.00 (t, J=7.3 Hz, 3H). ¹³ C {¹ H} NMR (CDCl₃) δ154.4, 138.6,129.5, 123.8, 119.2, 65.6 31.5, 19.6, 14.3. IR (CHCl₃) 3438, 1730; MS(FAB) m/z=194 (MH⁺). Anal. Calcd.: C, 68.37; H, 7.82; N, 7.25. Found: C,68.57; H, 7.95; N, 7.29.

EXAMPLE 23

4,4'-methylene-bis(cyclohexyl)-bis-(butylcarbamate) (21)

A 160 cc stainless steel Parr autoclave was charged with 3.15 g (0.03mol) 4,4'-methylenebis(cyclohexylamine), 6.9 g (0.035 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 35 mL CH₃ CN. Theautoclave was attached to a pressure head and at room temperature withstirring was added 160 psig carbon dioxide. Addition of CO₂ resulted inan exothermic reaction with a rise in temperature to ca. 40° C. Into aFischer-Porter bottle was added 8.33 g (0.09 mol) butyl chloride in 10mL CH₃ CN. This mixture was attached to a pressure head and 80 psigcarbon dioxide was added above the solution. After 1 h the butylchloride solution was added all at once under 80 psig CO₂ to thepre-formed carbamate anion solution generated in the autoclave. Afteraddition the pressure was raised to 160 psig with carbon dioxide and thereaction mixture was warmed to 85° C. for 6 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 100 mL ethylacetate and extracted with 2×100 mL 0.5M aq. HCl followed by 100 mLbrine. The organic layer was dried over Na₂ CO₃ filtered andconcentrated leaving a light yellow residue. This was passed through ashort column of silica gel using CH₂ Cl₂ as an eluent giving 5.48 g(89%) of the dibutyl carbamate 21. IR (CHCl₃) 3449, 1705; MS m/z=411(MH⁺). Anal. Calcd.: C, 67.28; H, 10.31; N, 6.82. Found: C, 67.27; H,10.09; N, 6.84.

EXAMPLE 24

TAN-Tributylcarbamate (22)

A 300 cc stainless steel Parr autoclave was added 17.3 g (0.1 mol)4-aminomethyl-1,8-octanediamine, 60 g (0.305 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 75 mL1-methyl-2-pyrrolidinone (N-MP). The autoclave was attached to apressure head and at room temperature with stirring was added 160 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction witha rise in temperature to ca. 40° C. Into a Fischer-Porter bottle wasadded 55.5 g (0.6 mol) butyl chloride. This mixture was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the butyl chloride solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in theautoclave. After addition the pressure was raised to 160 psig withcarbon dioxide and the reaction mixture was warmed to 85° C. for 18 h.After this time the reaction mixture was allowed to cool to roomtemperature and then the pressure was released. The crude material waspoured into 200 mL ethyl acetate and extracted with 2×200 mL 0.5M aq.HCl followed by 200 mL brine. The organic layer was dried over Na₂ CO₃,filtered and concentrated leaving a light yellow residue. This wascrystallized from ethyl acetate/hexane giving 36.5 g (85.5%) of thetributyl carbamate 22. m.p. 60°-61° C. ¹ H NMR (CDCl₃) δ4.85 (br, N--H,3H), 4.05 (t, J=6.6 Hz, 6H), 3.2-3.05 (m, 6H), 1.65-1.2 (overlapping m,23H), 0.93 (t, J=7.3 Hz, 9H). ¹³ C {¹ H} NMR (CDCl₃) δ157.7, 157.5,65.2, 65.1, 44.0, 41.5, 40.9, 38.6, 31.6, 31.5, 30.8, 28.9, 27.4, 24.0,19.6, 14.2. IR (CHCl₃) 3455, 1709. Anal. Calcd.: C, 60.86; H, 10.0; N,8.87. Found: C, 60.79; H, 10.38; N, 8.87.

EXAMPLE 25

N-phenyl-2-propylcarbamate (23)

Procedures as described in synthesis of 18, using1,8-diazabicyclo[5.4.0]undec-7-ene in place of CyTMG and 2-chloropropanein place of butyl chloride. A G.C. yield of 54% was calculated and a20.5% isolated yield of N-phenyl butylcarbamate resulted afterchromatography on silica gel. (A small amount of diphenyl urea wasdetected by G.C. in this particular reaction.) m.p. 88°-89 ° C.(literature m.p. 90° C.) ¹ H NMR (CD₂ Cl₂) δ7.46 (d, J=8.7 Hz, 2H), 7.35(t, J=8.0 Hz, 2H), 7.10 (t, J=7.5 Hz, 1H), 6.9 (br, N--H), 5.06 (7lines, J=6.3 Hz, 1H), 1.34 (d, J=6.3 Hz, 6H) . ¹³ C {¹ H} NMR (CD₂ Cl₂)δ154.2, 139.4, 129.8, 124.0, 119.5, 69.5, 22.8. IR (CHCl₃) 3437, 1728;MS (thermal spray) m/z=180 (MH⁺). Anal. Calcd.: C, 67.02; H, 7.31; N,7.82. Found: C, 67.35; H, 7.45; N, 7.85.

EXAMPLE 26

4,4'-methylene-bis(cyclohexyl)-bis-(2-methoxyethylcarbamate) (24)

Procedures as described in synthesis of 21, using 2-chloroethyl methylether in place of butyl chloride. A a 70% isolated yield of thedicarbamate 24 resulted after chromatography on silica gel. IR (CHCl₃)3441, 1715; MS m/z=415 (MH⁺). Anal. Calcd.: C, 60.85; H, 9.24; N, 6.76.Found: C, 60.68; H, 9.59; N, 6.80.

EXAMPLE 27

N-Cyclohexyl allylcarbamate (25)

A Fischer Porter bottle was charged with 1.98 g (0.02 mol) cyclohexylamine, 5.30 g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine, 154 mg (0.001 mol) biphenyl as internalG.C. standard, and 20 mL CH₃ CN. The Fischer-Porter bottle was attachedto a pressure head and at room temperature with stirring was added 80psig carbon dioxide. Addition of CO₂ resulted in an exothermic reactionwith a rise in temperature to ca. 40° C. Into a second Fischer-Porterbottle was added 4.6 g (0.06 mol) allyl chloride in 10 mL CH₃ CN. Thismixture was attached to a pressure head and 80 psig carbon dioxide wasadded above the solution. After 1 h the allyl chloride solution wasadded all at once under 80 psig CO₂ to the pre-formed carbamate anionsolution generated in the first Fischer-Porter bottle. After additionthe reaction mixture was warmed to 55° C. for 5 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. An aliquot was taken, diluted with diethyl ether,Cl⁻⁺ HCyTMG precipitated from solution and was filtered off, and by G.C.analysis a 97% yield of N-cyclohexyl allylcarbamate, 25, was calculated.

EXAMPLE 28

Piperazino-bis(allylcarbamate) (26)

A Fischer Porter bottle was charged with 12.9 g (0.15 mol) piperazine,62 g (0.41 mol) 1,8-diazabicycl[5.4.0]undec-7-ene and 90 mLN,N-dimethylformamide. The Fischer-Porter bottle was attached to apressure head and at room temperature with stirring was added 60 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction andcooling with ice was required. Into a second Fischer-Porter bottle wasadded 55 g (0.72 mol) allyl chloride in 15 mL DMF. This mixture wasattached to a pressure head and 60 psig carbon dioxide was added abovethe solution. After 1 h the allyl chloride solution was added all atonce under 60 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 50° C. for 3 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 300 mL 0.5Maqueous HCl. A heavy oil settled to the bottom. This oil was collected,dissolved in 100 mL diethyl ether, dried over Na₂ CO₃ filtered andconcentrated. Addition of hexane followed by cooling in the freezer gave32.8 g (86%) of the dicarbamate 26. m.p. 54°-55° C. ¹ H NMR (CDCl₃)δ5.94 (m, 2H), 5.31 (dq, J=17.2, 1.5 Hz, 2H), 5.23 (dq, J=10.3, 1.3 Hz,2H), 4.61 (dt, 5.6, 1.3 Hz, 4H), 3.5 (s, 8H). ¹³ C {¹ H} NMR (CDCl₃)δ155.5, 133.3, 118.2, 66.8, 44.1. IR (CHCl₃) 1690, 1649; MS (EI) m/z=254(MH⁺). Anal. Calcd.: C, 56.68; H, 7.13; N, 11.02. Found: C, 56.73; H,7.26; N, 11.03.

EXAMPLE 29

4,4'-methylene-bis(cyclohexyl)-bis-(allylcarbamate) (27)

A Fischer Porter bottle was charged with 2.1 g (0.01 mol)4,4'-methylene-bis(cyclohexylamine), 5.3 g (0.027 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 20 mL1-methyl-2-pyrrolidinone. The Fischer-Porter bottle was attached to apressure head and at room temperature with stirring was added 80 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction andcooling with ice was required. Into a second Fischer-Porter bottle wasadded 4.6 g (0.06 mol) allyl chloride in 10 mL N-MP. This mixture wasattached to a pressure head and 80 psig carbon dioxide was added abovethe solution. After 1 h the allyl chloride solution was added all atonce under 80 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 55° C. for 20 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 200 mL ethylacetate and extracted with 2×200 mL 0.5M aq. HCl followed by 200 mLbrine. The organic layer was dried over Na₂ CO₃, filtered andconcentrated leaving a light yellow solid. This was dissolved inmethylene chloride and passed through a short column of silica gel usingethyl acetate/CH₂ Cl₂ as eluent. Concentration of the filtrate gave 2.89g (76.5%) of the dicarbamate 27. IR (CHCl₃) 3441, 1713; MS (EI) m/z=379(MH⁺). Anal. Calcd.: C, 66.64; H, 9.05; N, 7.40. Found: C, 66.67; H,9.32; N, 7.36.

EXAMPLE 30

Hexamethylene-bis-1,6-(allylcarbamate) (28)

A 160 cc Parr autoclave was charged with 4.4 g (0.038 mol )1,6-diaminohexane, 15.4 g (0.10 mol) 1,8-diazabicycl[5.4.0]undec-7-ene,403 mg tridecane as internal G.C. standard and 30 mLN,N-dimethylformamide. The autoclave was attached to a pressure head andat room temperature with stirring was added 160 psig carbon dioxide.Addition of CO₂ resulted in an exothermic reaction with a rise intemperature to ca. 40° C. Into a Fischer-Porter bottle was added 12 g(0.157 mol) allyl chloride in 20 mL DMF. This mixture was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the allyl chloride solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in theautoclave. After addition the pressure was raised to 160 psig withcarbon dioxide and the reaction mixture was warmed to 65° C. for 17.5 h.After this time the reaction mixture was allowed to cool to roomtemperature and then the pressure was released. An aliquot was taken,diluted with diethyl ether, Cl⁻⁺ HDBU filtered off, and by G.C. a 40%yield of dicarbamate was calculated. The reaction mixture was pouredinto 150 mL water giving a white solid. This solid was collected byfiltration, washed with water and crystallized from CH₂ Cl₂ /hexanegiving 3.52 g (33%) of the dicarbamate 28. m.p. 72.5°-74° C. ¹ H NMR(CDCl₃) δ5.92 (m, 2H), 5.31 (dq, J=17.2, 1.6 Hz, 2H), 5.21 (dq, J=10.4,1.3 Hz, 2H), 4.89 (br, N--H, 2H), 4.56 (d, J=5.5 Hz, 4H), 3.20 (q, J=6.6Hz, 4H), 1.51 (m, 4H), 1.35 (m, 4H). ¹³ C {¹ H} NMR (CDCl₃) δ156.9,133.5, 118.0, 41.3, 30.4, 26.7. IR (CHCl₃) 3453, 1713, 1649; MS (EI)m/z=285 (MH⁺). Anal. Calcd.: C, 59.14; H, 8.51; N, 9.85. Found: C,59.30; H, 8.73; N, 9.70.

                                      TABLE 4                                     __________________________________________________________________________     ##STR8##                                                                                                          % Urethane                                                           Temp     G.C. Yield                                                                            Isolated                         Rxn #                                                                             RR'NH     R"Cl     Base.sup.2                                                                         (°C.)                                                                      Solvent.sup.3                                                                      (Compound #)                                                                          Yield                            __________________________________________________________________________    19  Bu.sub.2 NH                                                                             BuCl     CyTMG                                                                              80  CH.sub.3 CN                                                                        93.5(17)                                                                              --                               20  Et.sub.2 NH                                                                             BuCl     CyTMG                                                                              70  CH.sub.3 CN                                                                        97(18)  61                               21  BuNH.sub.2                                                                              BuCl     DBU  85  CH.sub.3 CN                                                                        82(19)  71                               21  BuNH.sub.2                                                                              BuCl     CyTMG                                                                              85  CH.sub.3 CN                                                                        73(19)  --                               22  PhNH.sub.2                                                                              BuCl     DBU  85  CH.sub.3 CN                                                                        67(20)  58                               23  1,4(NH.sub.2 Cy).sub.2 CH.sub.2                                                         BuCl     DBU  85  CH.sub.3 CN                                                                        --(21)  90                               23  1,4(NH.sub.2 Cy).sub.2 CH.sub.2                                                         BuCl     CyTMG                                                                              85  CH.sub.3 CN                                                                        --(21)  89                               24  Triaminononane.sup.1                                                                    BuCl     CyTMG                                                                              85  N-MP --(22)    85.5                           25  PhNH.sub.2                                                                              i-PrCl   DBU  90  CH.sub.3 CN                                                                        54(23)    20.5                           26  1,4(NH.sub.2 Cy).sub.2 CH.sub.2                                                         MeOCH.sub.2 CH.sub.2 Cl                                                                CyTMG                                                                              85  CH.sub.3 CN                                                                        --(24)  70                               27  CyNH.sub.2                                                                              CH.sub.2CHCH.sub.2 Cl                                                                  CyTMG                                                                              55  CH.sub.3 CN                                                                        97(25)  --                               28  HN(CH.sub.2 CH.sub.2).sub.2 NH                                                          CH.sub.2CHCH.sub.2 Cl                                                                  DBU  50  DMF  --(26)  86                               29  1,4(NH.sub.2 Cy).sub.2 CH.sub.2                                                         CH.sub.2CHCH.sub.2 Cl                                                                  CyTMG                                                                              55  NMP  --(27)    76.5                           30  H.sub.2 N(CH.sub.2).sub.6 NH.sub.2                                                      CH.sub.2CHCH.sub.2 Cl                                                                  DBU  65  DMF  40(28)  33                               __________________________________________________________________________     All reactions run under 80-160 psig carbon dioxide pressure and carried t     completion (limiting reagent = amine in all cases).                           G.C. Yields based on biphenyl as internal standard.                           .sup.1 Triaminononane = 4aminomethyl-1,8-octanediamine.                       .sup.2 CyTMG = Ncyclohexyl-N',N',N",N"-tetramethylguanidine.                  DBU = 1,8diazabicyclo[5.4.0]undec 7end.                                       .sup.3 NMP = 1methyl-2-pyrrolidinone.                                         DMF = N,Ndimethylformamide.                                              

EXAMPLE 31

Butyl-1,4-bis(N,N-dibutylcarbamate) (29)

A 300 cc stainless steel Parr autoclave was charged with 32.25 g (0.25mol) N,N-dibutyl amine 50.2 g (0.255 mol)N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 75 ml CH₃ CN. Theautoclave was attached to a pressure head and at room temperature withstirring was added 160 psig carbon dioxide. Addition of CO₂ resulted inan exothermic reaction with a rise in temperature to ca. 40° C. Into aFischer-Porter bottle was added 9.53 g (0.075 mol) 1,4-dichlorobutane in10 mL CH₃ CN. This mixture was attached to a pressure head and 80 psigcarbon dioxide was added above the solution. After 1 h thedichlorobutane solution was added all at once under 80 psig CO₂ to thepre-formed carbamate anion solution generated in the autoclave. Afteraddition the pressure was raised to 160 psig with carbon dioxide and thereaction mixture was warmed to 75° C. for 16 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. The crude material was poured into 200 mL ethylacetate and extracted with 2×200 mL 0.5M aq. HCl followed by 200 mLbrine. The organic layer was dried over Na₂ CO₃ filtered andconcentrated leaving a light yellow residue. This was chromatographed onsilica gel using ethyl acetate/hexane giving 21 g (70%) of thedicarbamate 29. Oil. ¹ H NMR (CDCl₃) δ4.1 (m, 4H), 3.2 (br m, 8H), 1.7(m, 4H), 1.51 (m, 8H), 1.30 (sextet, J=7.4 Hz, 8H), 0.92 (t, J=7.3 Hz,12H). ^(--C) {¹ H} NMR δ156.8, 65.1, (47.6, 47.1), (31.3, 30.8), 26.4,20.5, 14.3. IR (film) 1701; MS (FAB) m/z=401 (MH⁺). Anal. Calcd.: C,65.96; H, 11.07; N, 6.99. Found: C, 66.22; H, 11.12; N, 7.40.

EXAMPLE 32

Butyl-1,4-bis(N,N-diethylcarbamate) (30)

Procedures as described in synthesis of 29, using18-diazabicyclo[5.4.0]undec-7-ene in place ofN-cyclohexyl-N',N',N",N"-tetramethylguanidine and N,N-dimethylformamidein place of CH₃ CN. A G.C. yield of 96.5% was calculated using biphenylas internal standard. Oil ¹ H NMR (CDCl₃) δ4.1 (m, 4H), 3.26 (q, J=7 Hz,8H), 1.72 (m, 4H), 1.11 (t, J=7.1 Hz, 12H). ¹³ C {¹ H} NMR (CDCl₃)δ156.4, 65.1, 41.9, 26.4, 14.3. IR (film) 1696 (literature=1689); MSm/z=(MH⁺). Anal. Calcd.: C, 58.31; H, 9.79; N, 9.71. Found: C, 58.30; H,9.64; N, 9.72.

EXAMPLE 33

Butyl-1,4-bis(N,N-diallylcarbamate) (31)

Procedures as described in synthesis of 29, using1,8-diazabicyclo[5.4.0]undec-7-ene in place ofN-cyclohexyl-N',N',N",N"-tetramethylguanidine. Isolation by passage ofthe crude reaction material through silica gel using CH₂ Cl₂ as eluentgave a 88% isolated yield of the dicarbamate 31. Oil ¹ H NMR (CDCl₃)δ5.78 (m, 4H), 5.17 (overlapping br m, 8H) 4.14 (m, 4H), 3.87 (br, 8H),1.73 (m, 4H). ¹³ C {¹ H} NMR (CDCl₃) δ156.7, 134.1, 117.0 (br), 65.5,49.3 (br), 26.3. IR (film) 1700, 1644; MS (thermal spray) m/z=337 (MH⁺).Anal. Calcd.: C, 64.26; H, 8.39; N, 8.33. Found: C, 64.12; H, 8.62; N,8.32.

EXAMPLE 34

Butyl-1,4-bis(N-butylcarbamate) (32)

Procedures as described in synthesis of 29. A G.C. yield of 91.5% wascalculated using biphenyl as internal standard. Product isolated bypouring crude reaction material into water and collecting the whitesolid by filtration. After washing with water and air drying a 77%isolated yield of the dicarbamate 32 resulted. m.p. 114°-115° C. ¹ H NMR(CDCl₃) δ4.7 (br, N--H, 2H), 4.09 (br, 4H), 3.17 (br q, J=6 Hz, 4H),1.69 (br, 4H), 1.52-1.31 (overlapping m, 8H), 0.93 (t, J=7.2 Hz, 6H). ¹³C {¹ H} NMR (CDCl₃) δ157.2, 64.8, 41.2, 32.6, 26.2, 20.4, 14.2. IR(CHCl₃) 3453, 1711; MS (thermal spray) m/z=289 (MH⁺). Anal. Calcd.: C,58.31; H, 9.79; N, 9.71. Found: C, 58.71; H, 10.05; N, 9.80.

EXAMPLE 35

Ethyl-1,2-bis(N,N-diethylcarbamate) (33)

Procedures as described in synthesis of 29. A G.C. yield of 85% wascalculated using biphenyl as internal standard and an isolated yield of45% of the dicarbamate 33 resulted. Oil ¹ H NMR (CDCl₃) δ4.27 (s, 4H),3.27 (br q, J=6.3 Hz, 8H), 1.10 (t, J=7.2 Hz, 12H). ¹³ C {¹ H} NMR(CDCl₃) δ156.1, 63.8, 42.1 (br), 14.2 (br). IR (film) 1701; MS (thermalspray) m/z=261 (MH⁺).

                                      TABLE 5                                     __________________________________________________________________________     ##STR9##                                                                                                % Di-urethane                                                             Temp.                                                                             G.C. Yield                                                                            Isolated                                   Ex. #                                                                             RR'NH Base n =                                                                              Solvent                                                                            (°C.)                                                                      (Compound #)                                                                          Yield                                      __________________________________________________________________________    31  Bu.sub.2 NH                                                                         CyTMG                                                                              4  CH.sub.3 CN                                                                        75  --(29)  70                                         32  Et.sub.2 NH                                                                         DBU  4  DMF.sup.1                                                                          70  96.5(30)                                                                              --                                         33  Allyl.sub.2 NH                                                                      DBU  4  CH.sub.3 CN                                                                        70  --(31)  88                                         34  BuNH.sub.2                                                                          DBU  4  NMP.sup.2                                                                          85  44(32)  --                                         34  BuNH.sub.2                                                                          CyTMG                                                                              4  NMP.sup.2                                                                          85  91.5(32)                                                                              77                                         35  Et.sub.2 NH                                                                         CyTMG                                                                              2  CH.sub.3 CN                                                                        70  85(33)  45                                         __________________________________________________________________________     All reactions were run under 160 psig carbon dioxide pressure and were ru     to completion based on the starting dichloride.                               G.C. Yields are based on biphenyl as internal standard.                       .sup.1 DMF = N,Ndimethylformamide.                                            .sup.2 NMP = 1methyl-2-pyrrolidinone.                                    

The products resulting from the above-described process can be utilizedto prepare polyurethanes and polycarbonates. Such products can besubjected to any one of many polymerization conditions well known in theart, depending upon the desired end use, e.g., for polyurethanes, infibers, coatings, moulding applications and the like, and forpolycarbonates, in lenses, windows, telephone parts and the like. See,for example, Mark H.; Bikales N.; Overberger C.; Menges G.; KroschwitzJ. "Encyclopedia of Polymer Science and Engineering" 2nd Ed. John Wiley& Sons, New York 1985, which is hereby incorporated by reference.

In addition, living polymers can be prepared utilizing diamines,polyamines, diols, polyols or mixtures thereof and hydrocarbyl dihalidesor hydrocarbylpoly(halides). Where it is desired to produce livingpolymers having a weight average molecular weight (Mw) of less thanabout 10,000, the reaction can be conducted utilizing any of the basesdescribed above, such as the amidines or guanidines. However, where itis desired to utilize the carbamates and/or carbonates of the presentinvention to produce a living polymer having a Mw of greater than about10,000, it is necessary to conduct the reaction in the presence of abase that will not react with the hydrocarbyl halide (which would act toterminate chain propagation of the polymerization reaction). That is, anorganic nitrogenous base which is sufficiently sterically hindered suchthat reaction with the hydrocarbyl halide is minimized. A suitable testfor determining whether a particular base is suitable, i.e., issufficiently sterically hindered, is whether the base reacts with benzylchloride under conditions which simulate the polymerization reaction ofinterest. Specific suitable bases for use in such polymerizationreactions include the guanidine bases as previously described. Certainamidine bases are also sufficiently sterically hindered. An example ofone of such amidines is t-butyl dimethyl acetamidine. The followingExamples 36-39 illustrate preparation of polymer materials according tothe teaching of the present invention.

EXAMPLE 36

Oligo-urethane from piperazine, carbon dioxide and 1,4-dichlorobutane(chloro terminated) (34)

A 160 cc Parr autoclave was charged with 3.44 g (0.04 mol) piperazine,16.75 g (0.10 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 35mL CH₃ CN. The autoclave was attached to a pressure head and at roomtemperature with stirring was added 160 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a Fischer-Porter bottle was added 5.6 g (0.044 mol)1,4-dichlorobutane in 10 mL CH₃ CN. This mixture was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the dichlorobutane solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in theautoclave. After addition the pressure was raised to 160 psig withcarbon dioxide and the reaction mixture was warmed to 70° C. for 18 h.After this time the reaction mixture was allowed to cool to roomtemperature and then the pressure was released. The reaction mixture waspoured into 150 mL water giving a tan solid. This solid was collected byfiltration, washed with water, CH₃ CN and diethyl ether (7.27 g, IR(CHCl₃) 1688. M_(n) =3390 by NMR end group analysis.

EXAMPLE 37

Oligo-urethane from piperazine, carbon dioxide and 1,4-dichlorobutane(amine terminated) (35)

A 160 cc Parr autoclave was charged with 3.44 g (0.04 mol) piperazine,16.75 g (0.10 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 35mL CH₃ CN. The autoclave was attached to a pressure head and at roomtemperature with stirring was added 160 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a Fischer-Porter bottle was added 4.57 g (0.036 mol)1,4-dichlorobutane in 10 mL CH₃ CN. This mixture was attached to apressure head and 80 psig carbon dioxide was added above the solution.After 1 h the dichlorobutane solution was added all at once under 80psig CO₂ to the pre-formed carbamate anion solution generated in theautoclave. After addition the pressure was raised to 160 psig withcarbon dioxide and the reaction mixture was warmed to 70° C. for 18 h.After this time the reaction mixture was allowed to cool to roomtemperature and then the pressure was released. The reaction mixture waspoured into 150 mL 0.5M aqueous NaOH giving a tan solid. This solid wascollected by filtration, washed with water, CH₃ CN and diethyl ether(5.5 g, 64.4%). ¹ H NMR (CDCl₃) δ Oligomer backbone 4.17 (m), 3.49 (s),1.76 (m), Oligomer terminus 3.49 (shoulder) 2.86 (m). IR (CHCl₃) 3321(N--H), 1690. M_(n) (NMR end group analysis)=3250.

EXAMPLE 38

Chloro-terminated pre-polymer from 4,4'-methylene-bis(cyclohexylamine),carbon dioxide and 1,4-dichlorobutane (36)

10.5 g (0.05 mole) 4,4'-methylenebis(cyclohexylamine), 26.6 g (0.105mole) N-cyclohexyl-N',N',N",N"-tetraethyl guanidine and 40 mL1-methyl-2-pyrrolidinone were added to a 160 cc stainless steel Parrautoclave. With stirring, 350-400 rpm, carbon dioxide pressure was addedabove the reaction mixture, 160 psig, (r×n is exothermic, temperaturereached ca. 50° C.). After 1 h 7.62 g (0.06 mole) 1,4-dichlorobutane in10 mL N-MP was added all at once. The inlet of CO₂ was shut off and thereaction mixture was allowed to stir at 85° C. for 5 h. After this timethe reaction was allowed to cool to 40° C. and an additional 5 g (0.039mole) 1,4-dichlorobutane was added to the reaction mixture. The reactionwas heated to 85° C. for 14 h after which time the reaction was allowedto cool to room temperature and the pressure released. The crudereaction mixture (thick light yellow homogeneous solution) was slowlydripped into 200 ml water giving a white ppt. The ppt. was collected byfiltration and washed with water, acetonitrile and finally diethylether. The product was dried in a vacuum oven at 60° C. IR (CHCl₃) 3443,1707. M_(n) (NMR end group analysis)=1570.

EXAMPLE 39

Polyurethane from pre-polymer 36, carbon dioxide and Jeffamine-D-2000(37)

A 300 cc stainless steel Parr autoclave was charged with 10 g (0.005mol) Jeffamine-D-2000, 3.04 g (0.012 mol)N-cyclohexyl-N',N',N",N"-tetraethylguanidine, 8 g (ca. 0.005 mol) of thechloro-terminated pre-polyurethane 36 and 60 mL1-methyl-2-pyrrolidinone. The autoclave was attached to its pressurehead and 160 psig of carbon dioxide was added above the reaction mixtureAfter 1 h the mixture was heated to 105° C. for 3 d. After this periodof time the reaction was allowed to cool to room temperature and thepressure released. The thick yellow solution was slowly dripped intowater giving a stringy white solid. This solid was collected, washedwith water and air dried. IR (CHCl₃) 3441, 1709. GPC analysis: M_(n)=8000, M₂ =17800, M_(n) /M₂ =2.2.

EXAMPLE 40

This example illustrates the base effect on generation of polymers(polyurethanes) and demonstrates that guanidine bases must be utilizedto produce polyurethanes having a Mw of about 10,000 or greater. AFischer Porter bottle was charged with 2.1 g (0.01 mol)4,4'-methylene-bis(cyclohexylamine), 2 g (0.005 mol) Jeffamine-D-400,5.02 g (0.0325 mol) 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 10 mL1-methyl-2-pyrrolidinone (N-MP). The Fischer Porter bottle was attachedto a pressure head and at room temperature with stirring was added 80psig carbon dioxide. Addition of CO₂ resulted in an exothermic reactionwith a rise in temperature to ca. 40° C. Into a second Fischer-Porterbottle was added 2.62 g (0.015 mol) a,a'-dichloro-p-xylene in 15 mLN-MP. This was attached to a pressure head and 80 psig carbon dioxidewas added above the solution. After 1 h the dichloride solution wasadded all at once under 80 psig CO₂ to the pre-formed carbamate anionsolution generated in the first Fischer-Porter bottle. After additionthe reaction mixture was warmed to 55° C. for 2 d. Aliquots were takenafter 1 d and 2 d. Each aliquot was dripped slowly into water and thesolid collected by filtration, washed with water and air dried at roomtemperature. Molecular weight data was obtained by GPC-HPLC analysis andthe results are given in Table 6. The above reaction was repeated usingN-cyclohexyl-N',N',N",N"-tetramethylguanidine (CyTMG) andN-cyclohexyl-N',N',N",N"-tetraethylguanidine (CyTEG) in place of DBU.The results are given in Table 6. IR (CHCl₃) 3441, 1709.

                  TABLE 6                                                         ______________________________________                                         ##STR10##                                                                     ##STR11##                                                                    Rxn #  Base.sup.2                                                                             Rxn Time    M.sub.n                                                                            M.sub.w M.sub.w /M.sub.n                     ______________________________________                                        1      DBU      1d           600  1100   1.83                                                 2d           850  1750   2.05                                 2      CyTMG    1d          6050 13700   2.26                                                 2d          6350 13000   2.05                                 3      CyTEG    1d          6800 13150   1.93                                                 2d          7400 16300   2.2                                  ______________________________________                                         All reactions sampled after 1d and after 2d and molecular weight data was     obtained by GPCHPLC using polystyrene standards. In reaction #1 (DBU) onl     a small amount of polymer was obtained and the molecular weight data was      collected on this recovered material. In reactions #2 and #3 (CyTMG and       CyTEG) good yields of recovered segmented polyurethane/polypropylene oxid     resulted.                                                                     .sup.1 Jeffamine-D-400 is an amine terminated polypropylene oxide of          M.sub.n = 400 and was obtained from Texaco Inc.                               .sup.2 DBU = 1,8diazabicyclo[5.4.0]undec 7ene.                                CyTMG = Ncyclohexyl-N',N',N",N"-tetramethylguanidine.                         CyTEG = Ncyclohexyl-N',N',N",N"-tetraethylguanidine.                     

The following Examples 41-46 illustrate preparation of carbonatesaccording to the teachings of the present invention. For comparisonpurposes, these reactions are summarized in Table 7.

EXAMPLE 41

Benzylbutyl carbonate (38)

A Fischer Porter bottle was charged with 1.48 g (0.02 mol) butanol, 5.3g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 20 mL1-methyl-2-pyrrolidinone. The Fischer-Porter bottle was attached to apressure head and at room temperature with stirring was added 80 psigcarbon dioxide. Addition of CO₂ resulted in an exothermic reaction andcooling with ice was required. Into a second Fischer-Porter bottle wasadded 10.12 g (0.08 mol) benzyl chloride in 10 mL N-MP. This mixture wasattached to a pressure head and 80 psig carbon dioxide was added abovethe solution. After 1 h the benzyl chloride solution was added all atonce under 80 psig CO₂ to the pre-formed carbamate anion solutiongenerated in the first Fischer-Porter bottle. After addition thereaction mixture was warmed to 55° C. for 18 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. An aliquot was taken, diluted with diethyl ether,Cl⁻⁺ HCyTMG filtered off, and by G.C. analysis a 90% yield of benzylbutylcarbonate was calculated. The reaction was repeated in toluene andCH₃ CN as solvent with the results given in Table 7. The reaction wasrepeated using 1,8-diazabicyclo[[5.4.0]undec-7-ene in place ofN-cyclohexyl-N',N',N",N"-tetramethylguanidine with CH₃ CN and toluene assolvent; the results are given in Table 7. Oil ¹ H NMR (CDCl₃) 7.44-7.38(overlapping, m 5H), 5.20 (s, 2H), 4.20 (t, J=6.7 Hz, 2H), 1.70 (m, 2H),1.44 (m, 2H), 0.98 (t, J=7.3 Hz, 3H). ¹³ C{¹ H} NMR (CDCl₃) 155.8,136.0, 129.0, 128.8, 69.9, 68.5, 31.2, 19.4, 14.2. IR (film) 1746, 1262.

EXAMPLE 42

Benzyl i-propylcarbonate (39)

Procedures as described in synthesis of 38. The carbonate was isolatedby pouring the crude reaction mixture into diethyl ether, extractingwith 2×100 mL 0.5M aq. HCl and 1×100 mL brine, during over Na₂ CO₃,filtering, concentrating and chromatography on silica gel (85%, a smallamount of dibenzyl carbonate was detected and was separable fromproduct). Oil ¹ H NMR (CDCl₃) 7.44-7.35 (overlapping m, 5H), 5.19 (s,2H), 4.95 (7 line pattern, J=6.3 Hz, 1H), 1.34 (d, J=6.2 Hz, 6H). ¹³ C{¹H } NMR (CDCl₃) 155.2, 136.0, 129.1, 128.9, 128.8, 72.6, 69.7, 22.3. IR(film) 1740, 1260; MS (FAB) m/z=195 (MH⁺).

EXAMPLE 43

Dibenzyl carbonate (40)

Procedures as described in synthesis of 38. The carbonate was isolatedby pouring the crude reaction mixture into diethyl ether, extractingwith 2×100 mL 0.5M aq. HCl and 1×100 mL brine, during over Na₂ CO₃,filtering, concentrating and chromatography on silica gel (97%). Oil ¹ HNMR (CDCl₃) 7.45-7.35 (overlapping m, 10H), 5.25 (s, 4H). IR (film)1746, 1262.

EXAMPLE 44

Di-ethylene glycol-bis-benzylcarbonate (41)

Procedures as described in synthesis of 38. The carbonate was isolatedby pouring the crude reaction mixture into diethyl ether, extractingwith 2×100 mL 0.5M aq. HCl and 1×100 mL brine, during over Na₂ CO₃,filtering, concentrating and chromatography on silica gel (76%). Oil ¹ HNMR (CDCl₃) 7.43-7.34 (overlapping m, 10H), 5.20 (s, 4H), 4.33 (m, 4H),3.74 (m, 4H). ¹³ C{¹ H} NMR (CDCl₃) 155.6, 135.7, 129.1, 129.0, 128.9,70.2, 69.4, 67.5. IR (film) 1742, 1260; MS (FAB) m/z=375 (MH⁺). Anal.Calcd.: C, 64.16; H, 5.92. Found: C, 64.49; H, 6.19.

EXAMPLE 45

Dibutylcarbonate (42)

A 160 cc Parr autoclave was charged with 2.22 g (0.03 mol) butanol, 6.9g (0.035 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine and 30 mLCH₃ CN. The autoclave was attached to a pressure head and at roomtemperature with stirring was added 160 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a Fischer-Porter bottle was added 8.33 g (0.09 mol) butylchloride in 10 mL CH₃ CN. This mixture was attached to a pressure headand 80 psig carbon dioxide was added above the solution. After 1 h thebutyl chloride solution was added all at once under 80 psig CO₂ to thepre-formed carbamate anion solution generated in the autoclave. Afteraddition the pressure was raised to 160 psig with carbon dioxide and thereaction mixture was warmed to 85° C. for 16 h. After this time thereaction mixture was allowed to cool to room temperature and then thepressure was released. An aliquot was taken, diluted with diethyl ether,Cl⁻⁺ HCyTMG filtered off and by G.C. analysis a 73% yield of dibutylcarbonate was calculated. Oil ¹ H NMR (CDCl₃) 4.14(t, J=6.6 Hz, 4H),1.66 (m, 4H), 1.41 (m, 4H), 0.94 (t, J=7.3 Hz, 6H). ¹³ C{¹ H} NMR(CDCl₃) 155.9, 68.2, 31.2, 19.4, 14.1. IR (film) 1746, 1260; MS (FAB)m/z=175 (MH⁺).

EXAMPLE 46

Diethylene glycol-bis-allylcarbonate (43)

A Fischer Porter bottle was charged with 1.06 (0.01 mol) diethyleneglycol, 5.3 g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine,154 mg biphenyl as G.C. internal standard and 20 mL CH₃ CN. TheFischer-Porter bottle was attached to a pressure head and at roomtemperature with stirring was added 80 psig carbon dioxide. Addition ofCO₂ resulted in an exothermic reaction with a rise in temperature to ca.40° C. Into a second Fischer-Porter bottle was added 4.6 g (0.06 mol)allyl chloride in 10 mL CH₃ CN. This was attached to a pressure head and80 psig carbon dioxide was added above the solution. After 1 h the allylchloride solution was added all at once under 80 psig CO₂ to thepre-formed carbamate anion solution generated in the firstFischer-Porter bottle. After addition the reaction mixture was warmed to55° C. for 14 h. After this time the reaction mixture was allowed tocool to room temperature and then the pressure was released. An aliquotwas taken, diluted with diethyl ether, Cl⁻⁺ HCyTMG filtered off and byG.C. analysis a yield of 84% was calculated. The crude material waspoured into 100 mL diethyl ether and was then extracted with 2×100 mL0.5M aq. HCl and 100 mL brine. The ethereal layer was dried over Na₂CO₃, filtered and concentrated. The residue was chromatographed onsilica gel using 100% hexane to remove internal standard and then CH₂Cl₂ giving 2.2 g (80%) of the di-carbonate 43. Oil ¹ H NMR (CDCl₃) 5.91(m, 2H), 5.35 (dq, J=17.2, 1.4 Hz, 2H), 5.25 (dq, J=10.4, 1.4 Hz, 2H),4.62 (dt, J=5.8, 1.4 Hz, 4H), 4.28 (m, 4H), 3.72 (m, 4H). ¹³ C{¹ H} NMR(CDCl₃) 155.4, 132, 119.3, 69.4, 69.0, 67.3. IR (film) 1746, 1649, 1258.

                                      TABLE 7                                     __________________________________________________________________________     ##STR12##                                                                                                        % Carbonate                                                               Temp.                                                                             G.C. Yield                                                                            Isolated                          Ex. #                                                                             ROH      R'Cl     Base.sup.1                                                                         Solvent.sup.2                                                                      (°C.)                                                                      (Compound #)                                                                          Yield                             __________________________________________________________________________    41  BuOH     PhCH.sub.2 Cl                                                                          CyTMG                                                                              NMP  55  90(38)  --                                41  BuOH     PhCH.sub.2 Cl                                                                          CyTMG                                                                              CH.sub.3 CN                                                                        55  94(38)  --                                41  BuOH     PhCH.sub.2 Cl                                                                          DBU  CH.sub.3 CN                                                                        55  70.5(38)                                                                              --                                41  PhCH.sub.2 OH                                                                          BuCl     CyTMG                                                                              CH.sub.3 CN                                                                        85  53(38)  --                                42  i-PrOH   PhCH.sub.2 Cl                                                                          CyTMG                                                                              CH.sub.3 CN                                                                        55  --(39)  85                                43  PhCH.sub.2 OH                                                                          PhCH.sub.2 Cl                                                                          CyTMG                                                                              CH.sub.3 CN                                                                        55  --(40)  97                                44  O(CH.sub.2 CH.sub.2 OH).sub.2                                                          PhCH.sub.2 Cl                                                                          CyTMG                                                                              CH.sub.3 CN                                                                        55  --(41)  76                                45  BuOH     BuCl     CyTMG                                                                              CH.sub.3 CN                                                                        85  73(42)  --                                46  O(CH.sub.2 CH.sub.2 OH).sub. 2                                                         CH.sub.2CHCH.sub.2 Cl                                                                  CyTMG                                                                              CH.sub.3 CN                                                                        55  84(43)  80                                __________________________________________________________________________     All reactions were run under 80-160 psig carbon dioxide pressure and          carried to completion, limiting reagent = alcohol in all cases.               G.C. yields determined using biphenyl as internal standard.                   .sup.1 CyTMG = Ncyclohexyl-N',N',N",N"-tetramethylguanidine.                  DBU = 1,8diazabicycl[5.4.0]undec 7ene.                                        .sup.2 NMP = 1methyl-2-pyrrolidinone.                                    

EXAMPLE 47

This example illustrates the effect on relative rate of formation ofcarbamate and carbonate utilizing a polar aprotic solvent according tothe teachings of the present invention as opposed to a nonpolar solventas taught in Chemistry Express asset forth above. Thus, the rate forcarbamate production in a polar aprotic solvent is increased 300% overproduction in a nonpolar solvent. Similarly, carbonate production in apolar aprotic solvent is increased 100% over production in a nonpolarsolvent.

Into a Fischer-Porter bottle was charged 1.46 g (0.02 mol) diethylamine, 5.3 g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine,154 mg (0.001 mol) biphenyl as internal G.C. standard and 10 mL solvent(acetonitrile and toluene respectively). This was attached to a pressurehead and 80 psig carbon dioxide added above the reaction mixture. Into asecond Fischer-Porter bottle was added 10.12 (0.08 mol) benzyl chloridein 10 mL solvent. After 1 h the chloride solution was added all at onceto the diethyl carbamate anion solution under 80 psig CO₂ pressure. Thereaction was heated to 30° C. and monitored by G.C. A plot of %calculated carbamic acid, benzyl ester of diethyl carbamic acid producedvs. time for reactions run in acetonitrile and in toluene is shown inFIG. 1.

Into a Fischer-Porter bottle was charged 1.48 g (0.02 mol) butanol, 5.3g (0.027 mol) N-cyclohexyl-N',N',N",N"-tetramethylguanidine, 154 mg(0.001 mol) biphenyl as internal G.C. standard and 10 mL solvent(acetonitrile and toluene respectively). This was attached to a pressurehead and 80 psig carbon dioxide added above the reaction mixture. Into asecond Fischer-Porter bottle was added 10.12 (0.08 mol) benzyl chloridein 10 mL solvent. After 1 h the chloride solution was added all at onceto the diethyl carbonate anion solution under 80 psig CO₂ pressure. Thereaction was heated to 30° C. and monitored by G.C. A plot of %calculated carbonic acid, phenylmethyl ester of butyl carbonic acid, 38,produced vs. time for reactions run in acetonitrile and in toluene isshown in FIG. 2.

What is claimed is:
 1. A process for preparing urethanes comprising:(a)bringing CO₂ and an amine represented by the formula R₂ R₃ NH, whereinR₂ and R₃ together with the nitrogen form a saturated 5 to 9 memberedring radical, into reactive contact in the presence of a strongly basicnitrogenous compound selected from amidine and guanidine bases to formthe corresponding ammonium carbamate salt, and (b) reacting, in a polaraprotic solvent, said salt with a primary or secondary hydrocarbylhalide wherein the hydrocarbyl Group is selected from the groupconsisting of alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl andaralkenyl group.
 2. The process of claim 1 wherein said polar aproticsolvent is selected from the group consisting of dimethylsulfoxide,dimethylformamide, acetonitrile, N-methylpyrrolidone and mixturesthereof.
 3. The process of claim 2 wherein said polar aprotic solvent isselected from the group consisting of dimethylformamide andacetonitrile.
 4. The process of claim 1 wherein said primary orsecondary hydrocarbyl halide is represented by the formula R₁ X or XR₁X, wherein R₁ represents alkyl radicals having 1 to about 22 carbonatoms, alkenyl radicals having 2 to about 22 carbon atoms, cycloalkyland cycloalkenyl radicals having 3 to about 22 carbon atoms, and aralkyland aralkenyl radicals having 7 to about 22 carbon atoms, provided R₁ isnot a tertiary radical of the formula (R)₃ C-- or (R)₂ C═C(R)--, and Xrepresents a halide.
 5. The process of claim 4 wherein X is chloride. 6.The process of claim 1 wherein said basic nitrogenous compounds is aguanidine base.
 7. The process of claim 1 wherein said urethanes arerepresented by the formula: ##STR13## wherein R₁ represents alkylradicals having 1 to about 22 carbon atoms, alkenyl radicals having 2 toabout 22 carbon atoms, cycloalkyl and cycloalkenyl radicals having 3 toabout 22 carbon atoms, and aralkyl and aralkenyl radicals having 7 toabout 22 carbon atoms provided that R₁ is not a tertiary radical of theformula (R)₃ C-- or (R)₂ C═C(R)--, and R"₂ and R"₃ together with thenitrogen form a saturated 5 to 9 membered ring radical.
 8. The processof claim 7 wherein said polar aprotic solvent is selected from the groupconsisting of dimethylsulfoxide, dimethylformamide, acetonitrile,N-methylpyrrolidone and mixtures thereof.
 9. The process of claim 8wherein said polar aprotic solvent is selected from the group consistingof dimethylformamide and acetonitrile.
 10. The process of claim 7wherein said primary or secondary hydrocarbyl halide is represented bythe formula R₁ X or XR₁ X, wherein X represents a halide.
 11. Theprocess of claim 10 wherein X is chloride.
 12. The process of claim 7wherein said basic nitrogenous compound is a guanidine base.